A Highly Reactive Scandium Phosphinoalkylidene Complex: C H and H H Bonds Activation

A Highly Reactive Scandium Phosphinoalkylidene Complex: C H and H H Bonds Activation Weiqing Mao, Li Xiang, Carlos Alvarez Lamsfus, Laurent Maron,*, Xuebing Leng, Yaofeng Chen*, State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, P. R. China LPCNO, CNRS & INSA, Université Paul Sabatier, 135 Avenue de Rangueil, 31077 Toulouse, France Supporting Information Contents 1. General...S2 2. Synthesis of Li[CH(SiMe 3 )PPh 2 ](THF) and 1-7...S2 3. The isotopic labeling experiments...s8 4. X-ray crystallography for 1-7...S9 5. Molecular structures of 1, 3, 4 and 7...S13 6. NMR spectrum of Li[CH(SiMe 3 )PPh 2 ](THF) and 1-7...S15 7. The reversible process between 2 and 3...S38 8. 1 H and 2 H NMR spectrum of the reaction solution of 2 with pyridine-d 5...S40 9. 1 H, 1 H- 1 H gcosy and 2 H NMR spectrum of the product of the reaction of 2, D 2 and 1-hexene..... S42 10. 1 H 1 H NOESY spectrum of 3...S45 11. 1 H NMR spectral monitoring result of the metalation of 2 in C 6 D 6 at three different concentrations...s46 12. Computation details...s47 13. References...S85 S1

General. All operations were carried out under an atmosphere of argon using Schlenk techniques or in a nitrogen filled glovebox. Toluene, tetrahydrofuran, hexane, C 6 D 6 and THF-d 8 were dried over Na/K alloy, transferred under vacuum, and stored in the glovebox. CH 2 (SiMe 3 )PPh 2 and [LSc(Me)Cl] (L = [MeC(NDIPP)CHC(Me)(NDIPP)] -, DIPP = 2,6-( i Pr) 2 C 6 H 3 ) were synthesized as reported. 1,2 Pyridine, 1,3-dimethylpyrazole and 1-hexene were dried over activated 4 Å molecular sieves and degassed by three freeze-pump-thaw cycles before use. 4-dimethylamino pyridine was purified by sublimation. The highly pure H 2 (>99.9%) was further dried by passing through the activated 4 Å molecular sieves. 1 H, 13 C{ 1 H} and 31 P{ 1 H} NMR spectra were recorded on a Varian 400 MHz, an Agilent 400 MHz, an Agilent 500 MHz or an Agilent 600 MHz spectrometer. Chemical shifts were reported in δ units with references to the residual solvent resonance of the deuterated solvents for proton and carbon chemical shifts, to external H 3 PO 4 (85%) for phosphorus chemical shifts. The assignment of 1 H and 13 C{ 1 H} resonances was assisted with gcosy, ghsqc and ghmbc spectra. Elemental analysis was performed by the Analytical Laboratory of Shanghai Institute of Organic Chemistry. Li[CH(SiMe 3 )PPh 2 ](THF): Li[CH(SiMe 3 )PPh 2 ](THF) was synthesized by using the method reported by Peterson. 3 n-butyllithium (2.5 M in hexane, 8.82 mmol, 3.5 ml) was added to CH 2 (SiMe 3 )PPh 2 (2.40 g, 8.82 mmol) in 15 ml of THF at 0 o C. The reaction solution was allowed to warm to room temperature and stirred at room temperature for 2 h. The volatiles of the solution were removed under vacuum, the residue was washed with 5 2 ml of hexane and dried under vacuum to give Li[CH(SiMe 3 )PPh 2 ](THF) as a white solid (1.64 g, 53% yield). 1 H NMR (400 MHz, C 6 D 6, 25 o C): δ 7.63 (t, 3 J H-H = 7.4 Hz, 4H, o-phh of PPh 2 ), 7.16 (t, 3 J H-H = 7.3 Hz, overlapped with the residual solvent resonance of the deuterated solvent, m-phh of PPh 2 ), 7.07 (t, 3 J H-H = 7.2 Hz, 2H, p-phh of PPh 2 ), 3.42 (m, 4H, THF-H), 1.17 (m, 4H, THF-H), 0.29 (s, 9H, SiMe 3 ), 0.08 (s, 1H, PCHSi). 13 C{ 1 H}NMR (100 MHz,C 6 D 6, 25 o C): δ 147.9 (i-phc of PPh 2 ), 132.1 (d, 2 J P-C = 15.3 Hz, o-phc of PPh 2 ), 128.0 (d, 3 J P-C = 6.7 Hz, m-phc of PPh 2 ), 126.9 ( p-phc of PPh 2 ), 68.9 (THF-C), 25.3 (THF-C), 5.8 S2

(d, 1 J P-C = 26.8 Hz, PCHSi), 4.6 (d, 3 J P-C = 5.8 Hz, SiMe 3 ). 31 P{ 1 H} NMR (162 MHz, C 6 D 6, 25 o C): δ -4.26. Anal. Calcd for C 20 H 28 LiOPSi: C 68.55; H 8.05. Found: C 68.31; H 8.03. 1: [LSc(Me)Cl] (1.86 g, 3.63 mmol) and Li[CH(SiMe 3 )PPh 2 ](THF) (1.27 g, 3.63 mmol) were mixed in 10 ml of toluene. After stirring at room temperature for 0.5 h, the precipitate was moved by filtration. The volatiles of the solution were removed under vacuum, the residue was washed with 5 2 ml of hexane and dried under vacuum to give 1 as a pale yellow solid (1.79 g, 66% yield). 1 H NMR (400 MHz, C 6 D 6, 25 o C): δ 7.26 (m, 4H, o-phh of PPh 2 ), 7.17 (d, 3 J H-H = 7.6 Hz, overlapped with the residual solvent resonance of the deuterated solvent, m-arh of DIPP), 7.13 (t, 3 J H-H = 7.6 Hz, 2H, p-arh of DIPP), 6.99 (m, 6H, m-phh of PPh 2 and p-phh of PPh 2 ), 6.94 (d, 3 J H-H = 7.3 Hz, 2H, m-arh of DIPP), 5.11 (s, 1H, MeC(N)CH), 3.78 (sept, 3 J H-H = 6.8 Hz, 2H, CHMe 2 ), 2.83 (sept, 3 J H-H = 6.8 Hz, 2H, CHMe 2 ), 1.62 (s, 6H, CMe), 1.52 (d, 3 J H-H = 6.8 Hz, 6H, CHMe 2 ), 1.29 (d, 3 J H-H = 6.8 Hz, 6H, CHMe 2 ), 0.95 (d, 3 J H-H = 6.8 Hz, 6H, CHMe 2 ), 0.85 (d, 3 J H-H = 6.8 Hz, 6H, CHMe 2 ), 0.64 (s, 3H, ScMe), -0.26 (s, 9H, SiMe 3 ), -0.82 (s, 1H, PCHSi). 13 C{ 1 H}NMR (100 MHz, C 6 D 6, 25 o C): δ 168.4 (imine C), 145.8 (i-arc of DIPP), 143.4, 141.3 (o-arc of DIPP), 136.4 (d, 1 J P-C = 6.3 Hz, i-phc of PPh 2 ), 133.5 (d, 2 J P-C = 14.7 Hz, o-phc of PPh 2 ), 128.8 (d, 4 J P-C = 1.4 Hz, p-phc of PPh 2 ), 128.2 (d, 3 J P-C = 8.3 Hz, m-phc of PPh 2 ), 126.4 (p-arc of DIPP), 124.7, 124.4 (m-arc of DIPP), 97.2 (MeC(N)CH), 46.8 (d, 1 J P-C = 54.8 Hz, PCHSi), 34.1 (br, ScMe), 29.0, 28.9(CHMe 2 ), 26.5, 24.8, 24.3, 23.4 (CHMe 2 and CMe), 3.63 (d, 3 J P-C = 2.0 Hz, SiMe 3 ). 31 P{ 1 H}NMR (162 MHz, C 6 D 6, 25 o C): δ 14.84. Anal. Calcd for C 46 H 64 N 2 PScSi: C 73.76; H 8.61; N 3.74. Found: C 73.83; H 8.99; N 3.48. 2: 1 (473 mg, 0.63 mmol) was dissolved in 10 ml of THF. After standing at 50 o C for 14 h, the volatiles of the reaction solution were removed under vacuum, the residue was washed with 3 2 ml of hexane and dried under vacuum to give 2 as an orange solid (318 mg, 63% yield). 1 H NMR (400 MHz, THF-d 8, 25 o C): δ 7.23 (m, 6H, Ar-H), S3

6.88 (m, 10H, Ph-H), 5.07 (s, 1H, MeC(N)CH), 3.61 (m, 4H, THF-H), 3.42 (sept, 3 J H-H = 6.7 Hz, 2H, CHMe 2 ), 3.01 (sept, 3 J H-H = 6.7 Hz, 2H, CHMe 2 ), 1.77 (m, 4H, THF-H), 1.65 (s, 6H, CMe), 1.53 (d, 3 J H-H = 6.8 Hz, 6H, CHMe 2 ), 1.28 (d, 3 J H-H = 6.8 Hz, 6H, CHMe 2 ), 1.23 (d, 3 J H-H = 6.8 Hz, 6H, CHMe 2 ), 1.16 (d, 3 J H-H = 6.8 Hz, 6H, CHMe 2 ), -0.86 (s, 9H, SiMe 3 ). 13 C{ 1 H} NMR (100 MHz, THF-d 8, 25 o C): δ 168.3 (imine C), 151.7 (d, 1 J P-C = 103 Hz, PCSi), 147.34 (d, 1 J P-C = 6.0 Hz, i-phc of PPh 2 ), 146.5 (i-arc of DIPP), 142.9, 142.5 (o-arc of DIPP), 132.8 (d, 2 J P-C = 12.9 Hz, o-phc of PPh 2 ), 127.1 (d, 3 J P-C = 8.0 Hz, m-phc of PPh 2 ), 126.4 (p-arc of DIPP), 125.9 (d, 4 J P-C = 1.3 Hz, p-phc of PPh 2 ), 124.9, 124.6 (m-arc of DIPP), 97.1 (MeC(N)CH), 68.0 (THF-C), 29.7, 29.2 (CHMe 2 ), 26.2 (THF-C), 25.6, 25.5, 25.2, 24.9, 24.8, 24.4 (CHMe 2 and CMe), 4.7 (SiMe 3 ). 31 P{ 1 H}NMR (162 MHz, THF-d 8, 25 o C): δ 20.04. Anal. Calcd for C 49 H 68 N 2 OPScSi: C 73.10; H 8.51; N 3.48. Found: C 73.07; H 8.29; N 3.41. 3: 2 (100 mg, 0.12 mmol) was dissolved in 6 ml of toluene at room temperature. The volatiles of the solution were removed under vacuum, and this operation was repeated for three times to remove the THF from 2. 1 ml of hexane was added to the residue. After standing at -35 o C for 1 day, the solid was isolated, washed with 0.5 ml of cold hexane and dried under vacuum to give 3 as a yellow solid (63 mg, 69% yield). There are two isomers in 5:1 ratio; these two isomers are related to the stereogenic tertiary carbon of the isopropyl group bound to the scandium ion. The 1 H 1 H NOESY spectrum revealed that the major and minor diastereomers have the H and CH 3 on the tertiary carbon pointing towards the backbone of Nacnac ligand, respectively, and the major diastereomer has been subjected to XRD. The 1 H NMR spectral monitoring of the reaction in C 6 D 6 showed that the ratio of two isomers is constant during the reaction. 1 H NMR (500 MHz, C 6 D 6, 25 o C): δ 7.67-7.63 (m, 0.33H, Ar-H), 7.62-7.58 (m, 1.67H, Ar-H), 7.42 (d, 3 J H-H = 7.5 Hz, 0.84H, Ar-H), 7.27-7.22 (m, 1H, Ar-H), 7.20-6.84 (m, overlapped with the residual solvent resonance of the deuterated solvent, Ar-H), 6.82 (d, 3 J H-H = 7.5 Hz, 0.84H, Ar-H), 5.14 (s, 0.84H, MeC(N)CH), 5.10 (s, 0.16H, MeC(N)CH), 3.72-3.62 (m, 0.33H, CHMe 2 and S4

CH 2 CH(CH 3 )), 3.56 (sept, 3 J H-H = 6.8 Hz, 0.84H, CHMe 2 ), 3.38-3.24 (m, 1.67H, CHMe 2 and CH 2 CH(CH 3 )), 3.21 (sept, 3 J H-H = 6.8 Hz, 0.16H, CHMe 2 ), 2.81 2.70 (m, 1H, CHMe 2 ), 1.81 (s, 0.48H, CMe), 1.72 (s, 2.52H, CMe), 1.64 (s, 2.52H, CMe), 1.61 (s, 0.48H, CMe), 1.55 (m, CHMe 2 ), 1.50 (d, 3 J H-H = 7.2 Hz, 0.48H, CHMe 2 ), 1.44 (dd, 2 J H-H = 12.4 Hz, 3 J H-H = 4.7 Hz, 0.84H, CH 2 CH(CH 3 )), 1.32 (d, 3 J H-H = 6.9 Hz, 2.52H, CHMe 2 ), 1.25 (d, 3 J H-H = 6.8 Hz, 0.48H, CHMe 2 ), 1.19 (m, CHMe 2 ), 0.91 (d, 3 J H-H = 6.8 Hz, 2.52H, CHMe 2 ), 0.89 (d, 3 J H-H = 6.8 Hz, 0.48H, CHMe 2 ), 0.86 (br t, 0.84H, CH 2 CH(CH 3 )), 0.83 (d, 3 J H-H = 6.9 Hz, 0.48H, CHMe 2 ), 0.77 (d, 3 J H-H = 6.9 Hz, 2.52H, CHMe 2 ), -0.20 (s, 7.56H, SiMe 3 ), -0.21 (s, 1.44H, SiMe 3 ), -0.76 (s, 0.16H, PCHSi), -0.83 (s, 0.84H, PCHSi). 13 C{ 1 H}NMR (100 MHz, C 6 D 6, 25 o C) for the major isomer: δ 167.3, 166.6 (imine C), 147.7, 143.6, 142.9, 142.4 (o-arc of DIPP), 141.3, 137.9 (i-arc of DIPP), 136.5 (d, 1 J P-C = 10.3 Hz, i-phc of PPh 2 ), 134.1 (d, 2 J P-C = 15.0 Hz, o-phc of PPh 2 ), 133.7 (d, 2 J P-C = 15.1 Hz, o-phc of PPh 2 ), 129.1, 128.7 (p-phc of PPh 2 ), 128.2 (d, 3 J P-C = 8.2 Hz, m-phc of PPh 2 ), 128.0 (d, 3 J P-C = 8.6 Hz, m-phc of PPh 2 ), 127.0, 126.9, 124.8, 124.5, 123.4 (m-arc of DIPP and p-arc of DIPP), 98.6 (MeC(N)CH), 68.0 (ScCH 2 ), 40.3 (d, 1 J P-C = 50.5 Hz, PCHSi), 39.1 (CH 2 CH(CH 3 )), 29.4, 28.9, 28.5 (CHMe 2 ), 25.6, 25.3, 25.0, 24.9, 24.2, 24.1, 24.0, 23.4, 22.9 (CHMe 2 and CMe), 3.9 (d, 3 J P-C = 2.3 Hz, SiMe 3 ). 31 P{ 1 H}NMR (202 MHz, C 6 D 6, 25 o C): δ 20.37 (major), 19.38 (minor). Anal. Calcd for C 45 H 60 N 2 PScSi: C 73.74; H 8.25; N 3.82. Found: C 73.69; H 8.45; N 3.62. 4: 2 (100 mg, 0.12 mmol) and pyridine (42 mg, 0.53 mmol) were mixed in 5 ml of toluene. After standing at room temperature for 0.5 h, the volatiles of the reaction solution were removed under vacuum, the residue was washed with 3 1 ml of hexane and dried under vacuum to give 4 as a yellow solid (89 mg, 88% yield). 1 H NMR (400 MHz, C 6 D 6, 25 o C): δ 8.66 (d, 3 J H-H = 5.1 Hz, 1H, Py-H), 8.19 (d, 3 J H-H = 7.3 Hz, 1H, Py-H), 7.54 (m, 4H, o-phh of PPh 2 ), 7.27 (t, 3 J H-H = 7.1 Hz, 1H, Py-H), 7.09 (m, 12H, m-phh of PPh 2, p-phh of PPh 2 and Ar-H), 6.79 (t, 3 J H-H = 6.0 Hz, 1H, Py-H), 5.26 (s, 1H, MeC(N)CH), 3.13 (sept, 3 J H-H = 6.5 Hz, 2H, CHMe 2 ), 2.89 (sept, S5

3 J H-H = 6.7 Hz, 2H, CHMe 2 ), 1.62 (s, 6H, CMe), 1.09 (d, 3 J H-H = 6.7 Hz, 6H, CHMe 2 ), 0.89 (m, 12H, CHMe 2 ), 0.80 (d, 3 J H-H = 6.7 Hz, 6H, CHMe 2 ), -0.22 (s, 1H, PCHSi), -0.27 (s, 9H, SiMe 3 ). 13 C{ 1 H}NMR (100 MHz, C 6 D 6, 25 o C): δ 216.8 (ScC py ), 168.1 (imine C), 147.8 (i-arc of Dipp), 143.0 (Py-C), 142.5, 141.6 (o-arc of Dipp), 137.9 (d, 1 J P-C = 3.5 Hz, i-phc of PPh 2 ), 134.2 (d, 2 J P-C = 14.6 Hz, o-phc of PPh 2 ), 134.1 (Py-C), 130.5 (Py-C), 128.5 (d, 4 J P-C = 1.1 Hz, p-phc of PPh 2 ), 127.9 (d, 3 J P-C = 8.0 Hz, m-phc of PPh 2 ), 125.7 (p-arc of DIPP), 124.6, 124.1(m-ArC of DIPP), 121.5 (Py-C), 98.2 (MeC(N)CH), 37.8 (d, 1 J P-C = 55.4 Hz, PCHSi), 29.2, 28.7(CHMe 2 ), 25.2, 24.9, 23.6, 23.4 (CHMe 2 and CMe), 3.9 (d, 3 J P-C = 2.4 Hz, SiMe 3 ). 31 P{ 1 H}NMR (162 MHz, C 6 D 6, 25 o C): δ 18.84. Anal. Calcd for C 50 H 65 N 3 PScSi: C 73.95; H 8.07; N 5.17. Found: C 73.68; H 8.10; N 4.99. 5: 2 (100 mg, 0.12 mmol) and 4-dimethylamino pyridine (15 mg, 0.12 mmol) were mixed in 5 ml of toluene. After standing at room temperature for 0.5 h, the volatiles of the reaction solution were removed under vacuum, and 1 ml of hexane was added to the residue. After standing at room temperature overnight, the solid was isolated, washed with 1 ml of cold hexane and dried under vacuum to afford 5 as a yellow crystalline solid (83 mg, 78% yield). 1 H NMR (400 MHz, C 6 D 6, 25 o C): δ 8.44 (d, 3 J H-H = 6.1 Hz, 1H, Py-H), 7.61 (t, 3 J H-H = 7.5 Hz, 4H, o-phh of PPh 2 ), 7.38 (d, 4 J H-H = 2.2 Hz, 1H, Py-H), 7.18 7.05 (m, overlapped with the residual solvent resonance of the deuterated solvent, m-phh of PPh 2, p-phh of PPh 2 and Ar-H), 6.29 (dd, 3 J H-H = 6.2 Hz, 4 J H-H = 2.6 Hz, 1H, Py-H), 5.28 (s, 1H, MeC(N)CH), 3.20 (sept, 3 J H-H = 6.8 Hz, 4H, CHMe 2 ), 2.46 (s, 6H, NMe 2 ), 1.67 (s, 6H, CMe), 1.11 (d, 3 J H-H = 6.7 Hz, 6H, CHMe 2 ), 1.02 (d, 3 J H-H = 6.8 Hz, 6H, CHMe 2 ), 0.98 (m, 12H, CHMe 2 ), -0.21 (s, 1H, PCHSi), -0.23 (s, 9H, SiMe 3 ). 13 C{ 1 H}NMR (100 MHz, C 6 D 6, 25 o C): δ 213.1 (ScC py ), 167.8 (imine C), 152.9 (Py-CNMe 2 ), 148.1 (i-arc of Dipp), 142.8 (o-arc of Dipp), 142.1 (Py-C), 141.7 (o-arc of Dipp), 138.8 (i-phc of PPh 2 ), 134.4 (d, 2 J P-C = 14.9 Hz, o-phc of PPh 2 ), 128.3 (p-phc of PPh 2 ), 127.8 (d, 3 J P-C = 7.8 Hz, m-phc of PPh 2 ), 125.6 (p-arc of DIPP), 124.5, 124.1(m-ArC of DIPP), 110.5, 106.7 (Py-C), 98.0 (MeC(N)CH), 38.7 (NMe 2 ), 36.2 (d, 1 J P-C = 56.0 Hz, PCHSi), 29.1, S6

28.7(CHMe 2 ), 25.6, 25.3, 25.0, 23.8, 23.7 (CHMe 2 and CMe), 4.1 (d, 3 J P-C = 2.5 Hz, SiMe 3 ). 31 P{ 1 H} NMR (162 MHz, C 6 D 6, 25 o C): δ 17.11. Anal. Calcd for C 52 H 70 N 4 PScSi: C 73.03; H 8.25; N 6.55. Found: C 73.05; H 8.42; N 6.45. 6: 2 (100 mg, 0.12 mmol) and 1,3-dimethylpyrazole (26 mg, 0.27 mmol) were mixed in 5 ml of toluene. After standing at room temperature for 12 h, the volatiles of the reaction solution were removed under vacuum, and 1 ml of hexane was added to the residue. After standing at room temperature overnight, the solid was isolated, washed with 1 ml of cold hexane and dried under vacuum to afford 6 as a yellow crystalline solid (80 mg, 78% yield). 1 H NMR (400 MHz, C 6 D 6, 25 o C): δ 7.71 (t, 3 J H-H = 7.3 Hz, 4H, o-phh of PPh 2 ), 7.23 (d, 3 J H-H = 7.6 Hz, 2H, m-arh of DIPP), 7.16 (m, overlapped with the residual solvent resonance of the deuterated solvent, p-arh of DIPP), 7.03 (m, 6H, m-phh of PPh 2 and m-arh of DIPP), 6.90 (t, 3 J H-H = 7.3 Hz, 2H, p-phh of PPh 2 ), 6.32 (s, 1H, NCHCH), 5.34 (s, 1H, MeC(N)CH), 4.80 (s, 1H, NCHCH), 3.79 (br, 2H, CHMe 2 ), 2.96 (sept, 3 J H-H = 6.5 Hz, 2H, CHMe 2 ), 2.34 (s, 2H, ScCH 2 N), 1.68 (d, 3 J H-H = 5.9 Hz, 6H, CHMe 2 ), 1.53 (s, 6H, CMe), 1.47 (s, 3H, NCMe), 1.34 (d, 3 J H-H = 6.6 Hz, 6H, CHMe 2 ), 1.15 (s, 1H, PCHSi), 1.00 (d, 3 J H-H = 6.7 Hz, 6H, CHMe 2 ), 0.93 (br, 6H, CHMe 2 ), 0.10 (s, 9H, SiMe 3 ). 13 C{ 1 H}NMR (100 MHz, C 6 D 6, 25 o C): δ 168.1 (imine C), 147.0 (NC(CH)Me), 146.2 (i-arc of Dipp), 145.6 (d, 1 J P-C = 20.4 Hz, i-phc of PPh 2 ), 143.2, 143.0 (o-arc of Dipp), 133.7 (NCHCH), 133.2 (d, 2 J P-C = 17.1 Hz, o-phc of PPh 2 ), 127.9 (d, 3 J P-C = 7.1 Hz, m-phc of PPh 2 ), 127.6 (p-phc of PPh 2 ). 126.2 (p-arc of DIPP), 124.9, 124.2 (m-arc of DIPP), 105.0 (MeC(N)CH), 101.0 (NCHCH), 53.0 (ScCH 2 N), 41.7 (d, 1 J P-C = 64.9 Hz, PCHSi), 29.3, 28.7 (CHMe 2 ), 26.7, 25.8, 25.3, 25.2, 23.8 (CHMe 2 and CMe), 12.4 (NC(CH)Me), 4.3 (d, 3 J P-C = 6.7 Hz, SiMe 3 ). 31 P{ 1 H} NMR (162 MHz, C 6 D 6, 25 o C): δ -1.79. Anal. Calcd for C 50 H 68 N 4 PScSi: C 72.43; H 8.27; N 6.76. Found: C 71.98; H 8.33; N 6.67. 7: 2 (130 mg, 0.16 mmol) and 1-hexene (269 mg, 3.20 mmol) were mixed in 5 ml of toluene in a 25 ml tube with a Teflon stopcock. The tube was taken out of the S7

glovebox and connected to a Schlenk line. The solution was degassed and exposed to 1.0 atm of H 2 at room temperature. The tube was sealed and the reaction solution was allowed to warm to room temperature and stood at room temperature for 0.5 h. The volatiles of the solution were removed under vacuum, and 0.5 ml of cold hexane was added to the residue. After standing at -35 o C overnight, the solid was isolated, washed with 0.1 ml of cold hexane and dried under vacuum to afford 7 as a yellow crystalline solid (92 mg, 70% yield). 1 H NMR (400 MHz, C 6 D 6, 25 o C): δ 7.26-7.17 (m, 6H, o-phh of PPh 2 and m-arh of DIPP), 7.15 (t, 3 J H-H = 7.5 Hz, 2H, p-arh of DIPP), 7.02 6.97 (m, 6H, m-phh of PPh 2 and p-phh of PPh 2 ), 6.96 (dd, 3 J H-H = 7.5 Hz, 4 J H-H = 1.5 Hz, 2H, m-arh of DIPP), 5.17 (s, 1H, MeC(N)CH), 3.78 (sept, 3 J H-H = 6.9 Hz, 2H, CHMe 2 ), 2.77 (sept, 3 J H-H = 6.8 Hz, 2H, CHMe 2 ), 2.00 (m, 2H, CH 2 ), 1.61 (s, 6H, CMe), 1.60-1.49 (m, 12H, CHMe 2 and CH 2 ), 1.37 (d, 3 J H-H = 6.7 Hz, 6H, CHMe 2 ), 1.03 (m, 5H, ScCH 2 and CH 3 ), 0.95 (d, 3 J H-H = 6.8 Hz, 6H, CHMe 2 ), 0.81 (d, 3 J H-H = 6.9 Hz, 6H, CHMe 2 ), -0.26 (s, 9H, SiMe 3 ), -0.88 (s, 1H, PCHSi). 13 C{ 1 H}NMR (100 MHz, C 6 D 6, 25 o C): δ 168.4 (imine C), 146.0 (i-phc of Dipp), 143.5, 141.5 (o-arc of Dipp), 136.5 (d, 1 J P-C = 5.7 Hz, i-phc of PPh 2 ), 133.3 (d, 2 J P-C = 14.1 Hz, o-phc of PPh 2 ), 128.7 (p-phc of PPh 2 ), 128.2 (d, 3 J P-C = 8.2 Hz, m-phc of PPh 2 ), 126.3 (p-arc of DIPP), 124.7, 124.5 (m-arc of DIPP), 97.7 (MeC(N)CH), 59.9 (ScCH 2 ), 45.8 (d, 1 J P-C = 54.8 Hz, PCHSi), 37.2, 32.4, 30.3 (CH 2 ), 28.8 (CHMe 2 ), 26.4, 24.9, 24.8, 23.5 (CHMe 2, CMe and CH 2 ), 14.7 (CH 3 ), 3.7 (d, 3 J P-C = 2.1 Hz, SiMe 3 ). 31 P{ 1 H} NMR (162 MHz, C 6 D 6, 25 o C): δ 14.28. Anal. Calcd for C 51 H 74 N 2 PScSi: C 74.78; H 9.11; N 3.42. Found: C 74.93; H 9.17; N 3.39. Reaction of 2 with Pyridine-d 5 : Pyridine-d 5 (2.6 mg, 31 µmol) in 0.5 ml of C 6 D 6 was added to 2 (10 mg, 12 µmol) at room temperature. The mixed reaction solution was immediately transferred into a NMR tube. After standing at room temperature for 0.5 h, the 1 H NMR spectrum was recorded. The volatiles of the reaction solution were removed under vacuum, and 0.5 ml of C 6 H 6 was added to the residue for the 2 H NMR spectrum. S8

Reaction of 2, D 2 and 1-hexene. D 2 (1.2 ml, 54 µmol) was injected into a sealed tube containing 2 (10 mg, 12 µmol), 1-hexene (21 mg, 250 µmol) and 0.5 ml of C 6 D 6. After standing at room temperature for 1.5 h, the volatiles of the reaction solution were removed under vacuum (for removing the excess of 1-hexene). 0.5 ml of C 6 D 6 was added to the residue, and the 1 H NMR spectrum was recorded. The C 6 D 6 was removed under vacuum, and 0.5 ml of C 6 H 6 was added to the residue for the 2 H NMR spectrum. X-ray Crystallography. Single crystals of 1 and 4 were grown from the toluene solutions, those of 2, 3, 5, 6 and 7 were grown from the toluene/hexane mixed solutions. The single crystals of 1-7 were mounted under nitrogen atmosphere on a glass fiber at low temperature, and data collection was performed on a Bruker APEX2 diffractometer with graphite-monochromated Mo Kα radiation (λ = 0.71073 Å). The SMART program package was used to determine the unit cell parameters. The absorption correction was applied using SADABS program. 4 All structures were solved by direct methods and refined on F 2 by full-matrix least-squares techniques with anisotropic thermal parameters for non-hydrogen atoms. Hydrogen atoms were placed at calculated positions and were included in the structure calculation. Calculations were carried out using the SHELXL-97, SHELXL-2014 or Olex2 program. 5 Crystallographic data and refinement for 4 7 are listed in Table S1. S9

Table S1 Crystallographic Data and Refinement for 1 7. 1 2 3 formula C 46 H 64 N 2 PScSi C 49 H 68 N 2 OPScSi C 45 H 60 N 2 PScSi fw 749.01 805.07 732.97 color yellow orange yellow cryst syst. Monoclinic Triclinic Orthorhombic space group P 1 21 1 P -1 P c a 21 a, Å 10.6507(17) 11.5070(17) 16.606(2) b, Å 17.683(3) 11.7150(16) 12.2080(17) c, Å 12.0625(19) 19.688(4) 20.523(3) α, deg 90 92.184(3) 90 β, deg 106.144(3) 92.297(4) 90 γ, deg 90 118.486(2) 90 V, Å 3 2182.2(6) 2325.8(7) 4160.4(10) Z 2 2 4 D calcd, (mg/m 3 ) 1.140 1.150 1.170 F(000) 808 868 1576 T(K) 296.15 130 130 θ range, deg 1.758, 27.520 1.982, 27.579 1.668, 27.575 no. of refns collected 17923 19019 32419 no. of unique refns 6524 6153 5024 no. of obsd refns (I > 2σ(I)) 9668 10705 8013 No. of params 474 509 464 Final R, R w (I > 2σ(I)) 0.0542, 0.0859 0.0546, 0.1183 0.0486, 0.1003 Goodness-of-fit on F 2 0.976 0.963 0.992 ρ max, min, eå -3 0.264, -0.273 0.561, -0.584 0.696, -0.553 S10

4 5 6 formula C 50 H 65 N 3 PScSi C 52 H 70 N 4 PScSi C 50 H 68 N 4 PScSi fw 812.07 855.14 829.10 color yellow yellow yellow cryst syst. Monoclinic Orthorhombic Monoclinic space group P 1 21/c 1 P 21 21 21 C 1 c 1 a, Å 10.7039(11) 13.209(2) 12.8807(10) b, Å 21.309(2) 18.658(4) 19.5451(15) c, Å 20.142(2) 20.117(4) 18.7638(16) α, deg 90 90 90 β, deg 90.153(2) 90 91.203(2) γ, deg 90 90 90 V, Å 3 4594.3(8) 4958.1(16) 4722.8(7) Z 4 4 4 D calcd, (mg/m 3 ) 1.174 1.146 1.166 F(000) 1744 1840 1784 T(K) 130 130 130 θ range, deg 1.903, 30.535 1.489, 27.579 1.894, 30.646 no. of refns collected 45952 40052 23857 no. of unique refns 9254 9583 9968 no. of obsd refns (I > 2σ(I)) 13981 11406 11414 No. of params 547 558 528 Final R, R w (I > 2σ(I)) 0.0521, 0.1108 0.0548, 0.1321 0.0392, 0.0911 Goodness-of-fit on F 2 1.014 1.049 1.038 ρ max, min, eå -3 0.429, -0.423 1.052, -0.435 0.616, -0.340 S11

7 formula C 51 H 74 N 2 PScSi fw 819.14 color cryst syst. yellow Monoclinic space group P 1 21/n 1 a, Å 11.7644(11) b, Å 21.626(2) c, Å 19.3454(17) α, deg 90 β, deg 94.975(2) γ, deg 90 V, Å 3 4903.2(8) Z 4 D calcd, (mg/m 3 ) 1.110 F(000) 1776 T(K) 130 θ range, deg 1.883, 30.543 no. of refns collected 48998 no. of unique refns 7570 no. of obsd refns (I > 2σ(I)) 14982 No. of params 519 Final R, R w (I > 2σ(I)) 0.0575, 0.1309 Goodness-of-fit on F 2 0.980 ρ max, min, eå -3 0.525, -0.654 S12

Figure S1. Molecular structure of complex 1 (ball-and-stick representation). DIPP isopropyl groups and hydrogen atoms (except H31) were omitted for clarity. Selected bond distances [Å] and angles [ ]: Sc N1 2.144(4), Sc N2 2.169(4), Sc C30 2.230(5), Sc C31 2.292(4), Sc P 2.6379(15), C31 P 1.790(4), C31 Si 1.851(4), Sc C31 Si 139.6(2), Sc C31 P 79.47(17), Si C31 P 125.0(2). Figure S2. Molecular structure of complex 3 (ball-and-stick representation). DIPP isopropyl groups and hydrogen atoms (except H30) were omitted for clarity. Selected bond distances [Å] and angles [ ]: Sc N1 2.153(5), Sc N2 2.161(4), Sc C30 2.308(5), Sc C28 2.214(5), Sc P 2.7405(19), Sc C30 Si 130.7(3), Sc C30 P 82.83(18), Si C30 P 129.6(3). S13

Figure S3. Molecular structure of complex 4 (ball-and-stick representation). DIPP isopropyl groups and hydrogen atoms (except H30) were omitted for clarity. Selected bond distances [Å] and angles [ ]: Sc N1 2.1858(14), Sc N2 2.1873(15), Sc N3 2.1535(15), Sc C30 2.3487(17), Sc C46 2.2266(19), Sc P 2.6418(6), Sc C30 Si 144.73(9), Sc C30 P 78.16(7), Si C30 P 125.47(9). Figure S4. Molecular structure of complex 7 (ball-and-stick representation). DIPP isopropyl groups and hydrogen atoms (except H30) were omitted for clarity. Selected bond distances [Å] and angles [ ]: Sc N1 2.1523(19), Sc N2 2.173(2), Sc C30 2.292(2), Sc C46 2.206(3), Sc P 2.6798(8), Sc C30 Si 133.24(13), Sc C30 P 80.83(9), Si C30 P 126.41(13). S14

Figure S5. 1 H NMR spectrum of Li[CH(SiMe 3 )PPh 2 ](THF) (400 MHz, C 6 D 6, 25 o C). S15

Figure S6. 13 C{ 1 H} NMR spectrum of Li[CH(SiMe 3 )PPh 2 ](THF) (100 MHz, C 6 D 6, 25 o C). S16

Figure S7. 31 P{ 1 H} NMR spectrum of Li[CH(SiMe 3 )PPh 2 ](THF) (162 MHz, C 6 D 6, 25 o C). S17

Figure S8. 1 H NMR spectrum of 1(400 MHz, C 6 D 6, 25 o C). S18

Figure S9. 13 C{ 1 H} NMR spectrum of 1(100 MHz, C 6 D 6, 25 o C). S19

Figure S10. 31 P{ 1 H} NMR spectrum of 1(162 MHz, C 6 D 6, 25 o C). S20

Figure S11. 1 H NMR spectrum of 2(400 MHz, THF-d 8, 25 o C). S21

Figure S12. 13 C{ 1 H} NMR spectrum of 2(100 MHz, THF-d 8, 25 o C). S22

Figure S13. 31 P{ 1 H} NMR spectrum of 2(162 MHz, THF-d 8, 25 o C). S23

Figure S14. 1 H NMR spectrum of 3(500 MHz, C 6 D 6, 25 o C). S24

Figure S15. 13 C{ 1 H} NMR spectrum of 3(100 MHz, C 6 D 6, 25 o C). S25

Figure S16. 31 P{ 1 H} NMR spectrum of 3(202 MHz, C 6 D 6, 25 o C). S26

Figure S17. 1 H NMR spectrum of 4(400 MHz, C 6 D 6, 25 o C). S27

Figure S18. 13 C{ 1 H} NMR spectrum of 4(100 MHz, C 6 D 6, 25 o C). S28

Figure S19. 31 P{ 1 H} NMR spectrum of 4(162 MHz, C 6 D 6, 25 o C). S29

Figure S20. 1 H NMR spectrum of 5(400 MHz, C 6 D 6, 25 o C). S30

Figure S21. 13 C{ 1 H} NMR spectrum of 5(100 MHz, C 6 D 6, 25 o C). S31

Figure S22. 31 P{ 1 H} NMR spectrum of 5(162 MHz, C 6 D 6, 25 o C). S32

Figure S23. 1 H NMR spectrum of 6(400 MHz, C 6 D 6, 25 o C). S33

Figure S24. 13 C{ 1 H} NMR spectrum of 6(100 MHz, C 6 D 6, 25 o C). S34

Figure S25. 31 P{ 1 H} NMR spectrum of 6(162 MHz, C 6 D 6, 25 o C). S35

Figure S26. 1 H NMR spectrum of 7(400 MHz, C 6 D 6, 25 o C). S36

Figure S27. 13 C{ 1 H} NMR spectrum of 7(100 MHz, C 6 D 6, 25 o C). S37

Figure S28. 31 P{ 1 H} NMR spectrum of 7(162 MHz, C 6 D 6, 25 o C). S38

Figure S29. 1 H NMR spectra showing the reversible process between 2 and 3. a) 2 mins after dissolution of 2 in C 6 D 6 ; b) 30 mins after dissolution of 2 in C 6 D 6 ; c) 1 h after dissolution of 2 in C 6 D 6. d) 20 mins after addition of 1 equiv of THF to the above reaction solution; e) 40 mins after the addition of 1 equiv of THF. S39

Figure S30. 1 H NMR spectrum of the reaction solution of 2 with pyridine-d 5 at 25 o C (400 MHz, C 6 D 6, 25 o C). S40

Figure S31. 2 H NMR spectrum of the product of the reaction solution of 2 with pyridine-d 5 at 25 o C (600 MHz, C 6 H 6, 25 o C). S41

Figure S32. 1 H NMR spectrum of the product of the reaction of 2, D 2 and 1-hexene at 25 o C (400 MHz, C 6 D 6, 25 o C). S42

Figure S33. 1 H- 1 H gcosy spectrum of the product of the reaction of 2, D 2 and 1-hexene at 25 o C (400 MHz, C 6 D 6, 25 o C). S43

Figure S34. 2 H NMR spectrum of the product of the reaction of 2, D 2 and 1-hexene at 25 o C (600 MHz, C 6 H 6, 25 o C). S44

Figure S35. 1 H 1 H NOESY spectrum of 3. S45

Figure S36. The conversion curves of 2 in C 6 D 6 at room temperature. S46

Computational details Calculations were carried out with Gaussian09 6 at the DFT level, with the hybrid functional B3PW91. 7 Scandium and silicon atoms were treated with small-core pseudopotentials from the Stuttgart group, with additional polarization orbitals. 8 The other atoms that were part of the systems (phosphorus, nitrogen, carbon, and hydrogen) were treated with the extended all electron Gaussian-Type 6-31G** Pople basis set. 9 No symmetry constraints were considered for the geometry optimizations that took as starting point the experimentally obtained geometries of both reagents and products. Analytical calculations of the vibrational frequencies confirmed that the structures obtained were the critical points involved in the reactive process, and also obtained the thermal corrections over the energies. Transition states obtained where connected with its respective intermediates with Intrinsic Reaction Coordinate (IRC) calculations. Bonding was studied doing Natural Bond Orbital analysis over the optimized structures, with NBO software. 10 S47

Cartesian coordinates of all optimized structures 123 Scandium phosphino-alkylidene Sc -1.795928 0.114204 2.709490 P -0.600384 0.888628 4.886693 Si -2.512983-1.349351 6.110935 O 0.111248-0.002249 1.494023 N -2.767657 1.888124 1.719380 N -3.013340-1.179980 1.385987 C -6.517911 3.167561 2.300716 C -0.153277 4.522686 0.371895 C -0.177654-3.722927 2.734516 C -7.081528-1.980200 1.112549 C -3.709211-1.763247-0.913032 C -3.547461 3.005128-0.351249 C -3.123534 1.781514 0.437963 C -3.209447 0.571832-0.291369 C -3.273284-0.764074 0.139003 C -1.313502-1.762898 7.541698 C -3.941946-0.384908 6.930700 C 1.404273-1.037671 5.436026 C 2.701577-1.474513 5.705171 C 3.716360-0.549774 5.948623 C 3.420345 0.814300 5.925166 C 2.122249 1.246685 5.659720 C 1.089941 0.325719 5.415333 C 0.717822 3.917528 2.654069 C -0.433042 3.726056 1.656784 C -5.621396 2.391256 4.526428 C -5.284147 2.643398 3.049934 S48

C -1.777484 4.086716 2.275996 C -1.938092 5.365431 2.817732 C -3.136513 5.766900 3.394628 C -4.196375 4.871544 3.450849 C -4.092087 3.580306 2.922369 C -2.876153 3.191977 2.313178 C -6.304147-1.261043 3.397940 C -5.860677-1.625030 1.974195 C -0.601470-4.239760 0.296730 C -1.040621-3.401319 1.506895 C -4.818394-2.735461 2.005532 C -5.228212-4.026717 2.347962 C -4.326043-5.080687 2.421706 C -2.985412-4.845397 2.152874 C -2.521483-3.571730 1.807721 C -3.446376-2.505248 1.733167 C -0.447537 2.019772 7.525003 C -0.819292 2.923993 8.518570 C -1.738483 3.934957 8.240661 C -2.280738 4.034539 6.960348 C -1.906054 3.130982 5.967277 C -0.987534 2.106444 6.232637 C -3.220218-3.027573 5.556289 C -1.761933-0.404396 4.689574 C 1.603874-0.322580-0.312288 C 2.360620 0.344664 0.836608 C 1.469680 0.042678 2.030604 C 0.156665-0.018930 0.041741 H -3.424106 0.707922-1.345315 H -0.555757-0.766502-0.310893 H -0.159870 0.964831-0.320940 H 1.779680-1.403779-0.311433 H 1.874183 0.066458-1.297547 H 2.432206 1.425252 0.671646 H 3.371994-0.045677 0.975191 H 1.486230 0.798189 2.814957 H 1.685956-0.932939 2.474486 H 0.274660 1.242740 7.756866 H -0.390784 2.834988 9.513931 H -2.027497 4.640396 9.015462 H -2.992073 4.821941 6.725680 H -2.330583 3.223153 4.972448 H 0.608014-1.751157 5.241446 H 2.918181-2.540023 5.732104 S49

H 4.728032-0.886979 6.158615 H 4.203070 1.544310 6.117751 H 1.904981 2.312548 5.655960 H -3.722630-3.524296 6.395000 H -3.944062-2.922031 4.743760 H -2.425456-3.692405 5.203220 H -1.872847-2.249689 8.349870 H -0.513363-2.443791 7.235921 H -0.848339-0.864151 7.956266 H -3.597583 0.589378 7.291835 H -4.762346-0.211660 6.227478 H -4.345655-0.940829 7.785551 H -6.440443 1.670255 4.616018 H -4.759030 1.996520 5.069329 H -5.939436 3.313181 5.026109 H -6.314577 3.334721 1.238495 H -7.343304 2.451194 2.375953 H -6.867296 4.116810 2.721983 H -5.002772 1.683381 2.605229 H 0.837159 4.968887 2.936983 H 0.543270 3.335470 3.562338 H 1.666079 3.592548 2.209954 H 0.816914 4.237811-0.051467 H -0.914527 4.355416-0.395410 H -0.118767 5.598589 0.575673 H -0.464681 2.663746 1.393293 H -1.104393 6.061848 2.785472 H -3.239757 6.767947 3.804236 H -5.130563 5.177632 3.914719 H -1.178562-3.995362-0.601051 H 0.458526-4.070877 0.074308 H -0.728580-5.310803 0.487028 H -0.294489-4.767780 3.042298 H 0.884084-3.561543 2.514675 H -0.457419-3.086867 3.579276 H -0.870770-2.349616 1.255023 H -5.457966-0.924772 4.002754 H -7.051590-0.460179 3.375644 H -6.753145-2.123627 3.902513 H -7.659244-2.802729 1.547357 H -7.752414-1.117805 1.035684 H -6.799530-2.277983 0.097502 H -5.396566-0.734762 1.539493 H -6.277012-4.207957 2.567788 S50

H -4.665940-6.076604 2.691726 H -2.277189-5.668109 2.210832 H -3.015043 3.906908-0.049908 H -3.408460 2.841470-1.421920 H -4.613000 3.195580-0.183382 H -4.763388-2.025778-0.782144 H -3.589370-1.348829-1.915961 H -3.144322-2.695393-0.836077 125 Pyrazole s addition intermediate 1 Sc -2.039178 0.368175 2.552541 P -1.955984 2.724475 1.514676 Si -5.013661 2.580905 2.716405 N -2.147441-0.503996 4.621597 N -3.038155-1.457262 1.770480 N 1.211646 1.243448 2.952377 N 0.366573 0.368832 2.363589 C -3.468785 3.961483-0.584746 C -3.644557 4.465317-1.873282 C -2.609180 4.388194-2.804926 C -1.400311 3.796550-2.441305 C -1.233827 3.282729-1.155990 C -2.260444 3.364676-0.204328 C 0.004634 4.794121 1.702459 C 0.591009 5.928741 2.259185 C -0.015155 6.576754 3.337127 C -1.212643 6.080255 3.847669 C -1.794907 4.941577 3.289044 C -1.200077 4.281699 2.209609 C -2.319687 3.162640 6.356688 C -0.350910-3.525534 5.693641 C -2.991304-5.156792 2.507835 C -5.303617-0.489240-1.413273 C -5.336220-2.387777 1.882268 C -3.665234-1.549561 6.291040 C -3.278266-1.147818 4.883079 S51

C -4.228831-1.528639 3.901862 C -4.116300-1.757034 2.524323 C -5.327626 4.468465 2.857057 C -6.186014 1.964521 1.336462 C -5.735465 1.859920 4.328958 C -3.262520 2.043282 2.426964 C 1.573244-2.510575 4.417720 C 0.136578-2.297299 4.906673 C -3.398177 1.557912 7.949622 C -2.645539 1.687172 6.614586 C -0.041076-1.052375 5.759356 C 0.924135-0.747246 6.724100 C 0.760755 0.317269 7.602465 C -0.397350 1.079610 7.533148 C -1.396758 0.819207 6.587921 C -1.205028-0.247760 5.673639 C -3.049136 0.454422-1.964621 C -3.846972-0.360252-0.938913 C -0.560716-4.836403 1.965338 C -1.935195-4.153665 2.016794 C -3.221612-1.726438-0.709376 C -3.029294-2.543265-1.831460 C -2.513444-3.825506-1.727702 C -2.167102-4.311546-0.473896 C -2.326766-3.538131 0.678770 C -2.869039-2.227353 0.565880 C 0.452645-1.193535 0.440648 C 0.814513 2.045457 4.090655 C 2.380260 0.293351 1.348790 C 2.425739 1.220738 2.371313 C 1.071124-0.213352 1.376584 H -0.203379 2.406984 3.935588 H -0.153303-0.690168-0.321578 H 1.225230-1.764801-0.079198 H -0.198241-1.900508 0.958722 H 3.173975 0.021712 0.669124 H 3.223035 1.854590 2.731594 H 0.875896 1.470658 5.016831 H 1.472236 2.913855 4.142492 H 0.485535 4.308599 0.857040 H 1.522310 6.311762 1.848186 H 0.441203 7.463101 3.770043 H -1.700350 6.582802 4.679560 H -2.727483 4.552465 3.684210 S52

H -4.278072 4.035897 0.134109 H -4.590498 4.925697-2.147835 H -2.745187 4.783567-3.808068 H -0.590070 3.724517-3.162809 H -0.295970 2.800073-0.889249 H -5.277197 2.319847 5.210381 H -6.814878 2.044924 4.382048 H -5.570611 0.779164 4.379905 H -4.839625 5.053253 2.071186 H -6.405292 4.664158 2.800076 H -4.978939 4.859576 3.819152 H -6.166813 0.871115 1.284608 H -7.220332 2.275114 1.526947 H -5.894278 2.342594 0.351815 H -2.819035 1.991601 8.772677 H -4.350204 2.097638 7.900276 H -3.611574 0.518630 8.211548 H -1.826731 3.301771 5.393677 H -3.240435 3.756076 6.345296 H -1.671506 3.575049 7.138341 H -3.304375 1.358412 5.806540 H 2.257193-2.749572 5.239455 H 1.608436-3.353819 3.720834 H 1.959280-1.628199 3.899655 H -0.246618-4.439867 5.100422 H 0.235400-3.651994 6.610945 H -1.401474-3.427221 5.981547 H -0.502869-2.187678 4.024879 H 1.815129-1.364002 6.796428 H 1.522677 0.539955 8.344616 H -0.538086 1.899675 8.232284 H 0.216764-4.162992 1.592619 H -0.267700-5.173460 2.964671 H -0.567216-5.722524 1.321951 H -3.103359-5.982205 1.795416 H -2.697478-5.583912 3.473231 H -3.970757-4.688947 2.633012 H -1.881231-3.342110 2.749392 H -3.072976-0.014353-2.954933 H -3.466196 1.459652-2.063962 H -2.001298 0.559840-1.671381 H -5.915299-1.069018-0.717106 H -5.758855 0.500322-1.518710 H -5.354423-0.987440-2.388366 S53

H -3.844852 0.190343 0.010232 H -3.310245-2.162612-2.809403 H -2.385213-4.442293-2.613182 H -1.766579-5.317740-0.386174 H -4.495129-0.922880 6.635158 H -4.016479-2.584774 6.301690 H -2.841077-1.446330 6.996646 H -5.174365-1.850548 4.325823 H -5.070935-3.107222 1.106532 H -5.970888-2.879340 2.621710 H -5.927523-1.597902 1.405213 125 Pirazole s addition intermediate 2 Sc -0.278023 0.189259-0.147144 P 1.394097-2.758983-0.993616 Si -0.522057-1.813596-2.968901 N -2.475008 0.373532 0.300538 N -0.376756 2.183326-1.162128 N 2.575935 0.700042 1.335660 N 1.297485 0.318312 1.580803 C 1.927003-4.635499 1.023979 C 1.696186-5.351658 2.193502 C 0.619644-5.022286 3.021355 C -0.216713-3.970443 2.657870 C 0.032256-3.243656 1.489889 C 1.111095-3.547466 0.655466 C 0.730218-1.924958-4.410857 C -1.402834-3.508929-3.013540 C -1.827360-0.534751-3.519087 C -4.473975 2.706893 3.015861 C -4.484241-2.208895-0.802500 C 2.861847 1.368642-3.924326 C -0.709160 5.448299 0.968051 C -4.764594 1.173099-0.274274 C -2.079865 2.430676 3.706546 C -3.143981 2.008356 2.684991 S54

C -3.239318-4.000687 0.394468 C -3.299169-2.489962 0.138239 C -3.321654 0.495137 2.613494 C -3.802124-0.156185 3.754896 C -4.059409-1.518623 3.753923 C -3.868083-2.246780 2.585449 C -3.388381-1.653922 1.411578 C -3.070793-0.267698 1.441488 C -3.255778 1.162896-0.447010 C -2.804745 2.084455-1.407064 C 0.958217 4.074522 2.258401 C 0.115711 4.152221 0.976311 C 0.734474 2.429819-4.706017 C 1.499285 1.915225-3.475725 C 0.982699 4.030352-0.269591 C 2.049393 4.925043-0.415051 C 2.885637 4.879816-1.520982 C 2.677958 3.904190-2.488244 C 1.636248 2.975172-2.390199 C 0.755856 3.062964-1.280408 C -1.602999 3.920971-2.469377 C -1.539671 2.647783-1.641874 C 3.816278-1.753485-1.946983 C 5.153857-1.367946-1.920657 C 5.870316-1.392276-0.721139 C 5.224068-1.801130 0.444799 C 3.877248-2.170795 0.416878 C 3.142132-2.155781-0.779078 C 0.247264-1.390143-1.306690 C 3.040194 1.050218 0.008007 C 0.027757-0.483148 3.585035 C 3.307961 0.696527 2.460350 C 2.488111 0.292495 3.495270 C 1.239329 0.053152 2.903821 H -0.878001-0.385420 2.984311 H 0.165927-1.545788 3.804144 H -0.142243 0.037946 4.531074 H 2.753585 0.161648 4.533461 H 4.354003 0.964598 2.435145 H 2.978518 2.127043-0.155811 H 4.068418 0.701367-0.100304 H 2.752382-4.923060 0.376556 H 2.349012-6.181292 2.454054 H 0.428529-5.590674 3.927682 S55

H -1.075327-3.714833 3.275085 H -0.649179-2.447012 1.199245 H 3.397442-2.484417 1.339186 H 5.770245-1.837562 1.385210 H 6.920553-1.112887-0.701291 H 5.646003-1.067468-2.842648 H 3.278458-1.753657-2.891488 H -1.399518 0.463901-3.650106 H -2.261903-0.840310-4.478212 H -2.642887-0.453795-2.794471 H 1.456095-2.723848-4.225932 H 0.210463-2.156965-5.348513 H 1.278465-0.989673-4.553893 H -1.693270-3.758739-4.041094 H -0.739522-4.298733-2.647217 H -2.307684-3.510019-2.400667 H 1.242458 3.295453-5.147770 H 0.680388 1.646531-5.469324 H -0.288551 2.726780-4.466873 H 3.465131 1.020150-3.081565 H 2.717970 0.522073-4.601674 H 3.443957 2.116293-4.474397 H 0.932532 1.078750-3.049313 H 1.671160 4.903396 2.322531 H 0.315498 4.131635 3.142023 H 1.526185 3.141503 2.314282 H -1.357792 5.498238 1.849527 H -0.058085 6.329513 0.984911 H -1.341161 5.522280 0.079437 H -0.584363 3.309840 0.980972 H 2.218514 5.678148 0.350126 H 3.699427 5.592263-1.625911 H 3.345117 3.861078-3.343422 H -1.088329 2.058494 3.438699 H -2.024287 3.523204 3.765239 H -2.319709 2.060405 4.709470 H -4.789732 2.493224 4.042780 H -4.367308 3.793478 2.925387 H -5.281300 2.386205 2.352729 H -2.814940 2.362039 1.703645 H -4.201745-4.389625 0.748697 H -3.010988-4.518710-0.541034 H -2.467068-4.275249 1.116249 H -4.475145-1.191681-1.194477 S56

H -4.448767-2.888006-1.660614 H -5.437938-2.372311-0.286652 H -2.379079-2.200961-0.388664 H -4.107681-3.304382 2.580760 H -4.429600-2.009601 4.649958 H -3.985671 0.422269 4.656872 H -2.239240 3.754723-3.343632 H -2.069703 4.722362-1.887504 H -0.628135 4.271373-2.802376 H -3.606827 2.571919-1.952453 H -5.127767 0.380937 0.378791 H -5.084698 2.135274 0.137391 H -5.244724 1.072172-1.252409 H 2.437963 0.511821-0.730051 125 Pyrazole s addition transition state Sc -1.311465-0.414696-1.833052 P 0.449700-3.560837-2.623900 Si -1.362128-2.378385-4.564127 N -3.504850-0.200778-1.326640 N -1.456723 1.606282-2.829859 N 1.070633-0.270825-0.339030 N -0.173200-0.500307 0.148885 C 0.911112-5.464359-0.637553 C 0.695356-6.153206 0.551390 C -0.278301-5.713729 1.451135 C -1.025117-4.579470 1.144388 C -0.789832-3.879619-0.041989 C 0.184500-4.299886-0.950367 C -0.139958-2.488877-6.027470 C -2.312617-4.029502-4.625562 C -2.647830-1.057999-5.059731 C -5.532503 2.161755 1.377214 C -5.383200-2.866406-2.388812 C 1.886200 0.809797-5.348211 C -1.858714 4.839834-0.562026 S57

C -5.818351 0.530972-1.894682 C -3.123288 1.885410 2.024527 C -4.209616 1.459920 1.028317 C -4.090252-4.591169-1.138647 C -4.203916-3.089634-1.425524 C -4.374690-0.054727 0.977007 C -4.868669-0.693738 2.119761 C -5.084125-2.063345 2.146152 C -4.833300-2.814095 1.003516 C -4.345654-2.231503-0.172003 C -4.079512-0.835429-0.171118 C -4.311177 0.557833-2.075482 C -3.888067 1.479301-3.051458 C -0.061030 3.450758 0.533548 C -0.994710 3.575934-0.681104 C -0.103306 1.850938-6.468635 C 0.481671 1.391087-5.124114 C -0.192010 3.541088-1.974557 C 0.783865 4.525011-2.166073 C 1.589949 4.536848-3.295028 C 1.456762 3.518271-4.228620 C 0.506924 2.501704-4.081996 C -0.367130 2.543988-2.966467 C -2.688712 3.327580-4.126719 C -2.632825 2.056453-3.300255 C 2.884794-2.668197-3.675854 C 4.229575-2.305829-3.680569 C 4.968130-2.328014-2.496298 C 4.341793-2.713061-1.312451 C 2.989084-3.058848-1.306977 C 2.231430-3.040949-2.487906 C -0.563845-2.062325-2.871928 C 1.179755-0.046200-1.764367 C -1.165976-1.116164 2.355555 C 1.994156-0.361392 0.630593 C 1.329263-0.662720 1.808404 C -0.027996-0.749492 1.465822 H -2.102215-1.191138 1.801814 H -0.968392-2.082648 2.828284 H -1.300041-0.379242 3.153510 H 1.764798-0.823166 2.783633 H 3.041654-0.223796 0.407449 H 1.163002 1.022864-1.987883 H 2.124457-0.464761-2.113241 S58

H 1.653999-5.833274-1.341536 H 1.277458-7.044891 0.770762 H -0.460408-6.259570 2.373072 H -1.804441-4.238395 1.821422 H -1.387705-3.004085-0.276853 H 2.518708-3.347966-0.372225 H 4.906959-2.745390-0.383414 H 6.021057-2.059011-2.500177 H 4.706800-2.020578-4.614900 H 2.328480-2.664516-4.609002 H -2.225724-0.058635-5.193240 H -3.092437-1.357407-6.016394 H -3.463191-0.983632-4.333647 H 0.530207-3.345939-5.904244 H -0.691931-2.632277-6.964175 H 0.469891-1.587864-6.131556 H -2.682780-4.199868-5.643840 H -1.664790-4.866871-4.352158 H -3.173217-4.025617-3.952789 H 0.473963 2.685425-6.883150 H -0.075117 1.031178-7.194291 H -1.143837 2.174242-6.380399 H 2.331560 0.446388-4.418885 H 1.841925-0.029261-6.048664 H 2.567440 1.550193-5.780547 H -0.153375 0.586456-4.739063 H 0.638049 4.292084 0.587630 H -0.636645 3.441637 1.464209 H 0.529505 2.530733 0.490941 H -2.424250 4.831510 0.376061 H -1.243446 5.746272-0.567100 H -2.577211 4.921122-1.382759 H -1.666686 2.711314-0.678694 H 0.909471 5.299712-1.413865 H 2.329636 5.320079-3.436563 H 2.108396 3.508268-5.097732 H -2.144319 1.489940 1.743971 H -3.049546 2.977631 2.064139 H -3.353767 1.534676 3.036687 H -5.829903 1.962080 2.412337 H -5.426252 3.246961 1.272257 H -6.353099 1.835109 0.733029 H -3.898986 1.805976 0.038398 H -5.043250-5.009826-0.793618 S59

H -3.824676-5.119116-2.058919 H -3.321422-4.819419-0.397317 H -5.405941-1.854036-2.793943 H -5.312941-3.556472-3.235942 H -6.336795-3.056315-1.882400 H -3.285626-2.781512-1.943942 H -5.034371-3.879595 1.019759 H -5.462816-2.543839 3.044255 H -5.088783-0.100880 3.003907 H -3.644645 3.405514-4.647159 H -2.583104 4.206482-3.482775 H -1.879481 3.383238-4.855405 H -4.704766 1.941159-3.595044 H -6.159778-0.281339-1.254870 H -6.158806 1.477017-1.462453 H -6.300175 0.438482-2.872771 H 0.424835-0.967725-2.498683 125 Pyrazole s addition final product Sc -0.148530 0.330102-0.091384 P 1.945140-2.528768-1.423573 Si -0.525778-1.946910-2.966573 N -2.317310 0.628249 0.513335 N -0.394788 2.191686-1.315354 N 1.581672 0.506872 2.020020 N 0.536011-0.356746 2.032774 C 2.491057-4.811490 0.033642 C 2.245841-5.888084 0.877217 C 1.013086-6.003318 1.522658 C 0.043733-5.025375 1.320742 C 0.300830-3.929152 0.491739 C 1.527340-3.805457-0.166170 C 0.406551-1.961594-4.627148 C -1.126273-3.722794-2.662403 C -2.067055-0.868530-3.242414 C -3.239174 3.298099 3.290563 C -4.721022-1.886306-0.441895 S60

C 2.787815 0.999536-3.609445 C -1.249627 5.528251 0.036196 C -4.628197 1.491557 0.139262 C -1.124052 2.223889 4.123040 C -2.202937 2.193811 3.031021 C -3.385731-3.583163 0.807622 C -3.487202-2.093759 0.451893 C -2.854796 0.824097 2.921011 C -3.484902 0.300763 4.055408 C -4.131557-0.925807 4.025054 C -4.120392-1.669890 2.851480 C -3.485332-1.207185 1.693301 C -2.874609 0.073585 1.722030 C -3.168629 1.325098-0.247316 C -2.821071 2.036974-1.412468 C 0.495604 4.958801 1.745793 C -0.183116 4.500127 0.448398 C 1.289189 2.375592-5.076377 C 1.514858 1.855544-3.647387 C 0.801845 4.242368-0.683649 C 1.828736 5.164856-0.896355 C 2.736831 5.014515-1.936769 C 2.607917 3.929546-2.789214 C 1.589363 2.981260-2.628852 C 0.681453 3.126125-1.555524 C -1.649921 3.474457-3.026465 C -1.581299 2.514595-1.855687 C 4.464212-1.331007-1.437253 C 5.650276-0.824267-0.907512 C 5.826119-0.766121 0.473858 C 4.808321-1.213329 1.316268 C 3.614839-1.699466 0.784382 C 3.419638-1.758993-0.603352 C 0.558387-1.276285-1.533060 C 1.706398 1.265531 0.789272 C -0.395173-2.057920 3.606444 C 2.283915 0.429941 3.159619 C 1.674549-0.528819 3.957864 C 0.581863-1.002706 3.214019 H -1.393202-1.837262 3.223829 H -0.088357-3.035372 3.220080 H -0.453524-2.129635 4.695528 H 1.971047-0.845243 4.947444 H 3.154651 1.049835 3.314801 S61

H 1.705047 2.336678 1.001990 H 2.640399 0.997580 0.282143 H 3.444897-4.744378-0.484858 H 3.011025-6.646625 1.021210 H 0.808713-6.852353 2.169337 H -0.921326-5.118263 1.811255 H -0.457803-3.164709 0.350103 H 2.836487-2.052443 1.454441 H 4.942892-1.188819 2.394605 H 6.756376-0.389793 0.891464 H 6.444302-0.497410-1.573968 H 4.351971-1.422413-2.514650 H -1.798829 0.149600-3.540488 H -2.677131-1.298661-4.045389 H -2.693183-0.794450-2.348959 H 1.346640-2.514540-4.544630 H -0.205694-2.441775-5.399297 H 0.631714-0.946333-4.969936 H -1.719939-4.052872-3.522643 H -0.292346-4.420440-2.542340 H -1.755850-3.798646-1.772145 H 2.147133 2.962207-5.422601 H 1.163783 1.537863-5.771108 H 0.405642 3.015136-5.152715 H 3.009258 0.652930-2.597446 H 2.689524 0.124378-4.259948 H 3.654957 1.573655-3.954889 H 0.661794 1.220920-3.382032 H 0.937306 5.956292 1.647600 H -0.242205 5.017389 2.552665 H 1.287432 4.272525 2.060074 H -1.949243 5.709418 0.859936 H -0.783889 6.485434-0.225412 H -1.830829 5.191516-0.825697 H -0.694546 3.554721 0.654070 H 1.916746 6.022390-0.235347 H 3.530986 5.741241-2.084769 H 3.307156 3.814664-3.613343 H -0.365041 1.455023 3.962684 H -0.625920 3.198722 4.139750 H -1.557749 2.063685 5.116573 H -3.742588 3.148561 4.252250 H -2.753645 4.279572 3.322238 H -4.010510 3.329053 2.516499 S62

H -1.718374 2.406486 2.073527 H -4.331780-3.968591 1.203744 H -3.152200-4.172800-0.083615 H -2.610655-3.769487 1.554712 H -4.762520-0.885904-0.875126 H -4.709951-2.603521-1.269538 H -5.642083-2.047317 0.130184 H -2.603130-1.827152-0.142138 H -4.610632-2.638049 2.835854 H -4.631285-1.307543 4.911149 H -3.478190 0.878172 4.976217 H -2.668604 3.829342-3.190159 H -0.990896 4.334020-2.893634 H -1.322336 2.957754-3.934914 H -3.670817 2.412988-1.970131 H -5.006981 0.699696 0.782711 H -4.748059 2.438964 0.675948 H -5.250560 1.553964-0.756737 H 1.099529-0.463487-2.067086 125 Pyrazole s addition intermedate 2 (isomer) Sc -2.381724 1.824376 2.875715 P -1.665921 4.147200 5.374884 Si -1.917728 1.398600 6.292393 N -4.287181 0.639878 2.665944 N -2.895462 4.334634 0.627191 N -2.039532 3.592053 1.377460 N -1.254021 0.017076 2.168254 C -3.103236-1.493914 2.679588 C -1.406347-1.176643-1.562939 C 2.380360 1.085132 4.264737 C -6.386288-0.452114-0.700233 C -6.235974 0.343060 5.491976 C -4.909929 1.519974-1.168852 C -5.415120 0.565472-0.077896 C -6.520682 2.786112 5.857654 C -5.884352 1.735529 4.939561 C -6.063453 1.303504 1.088865 C -7.244624 2.009702 0.832537 C -7.935692 2.652215 1.848283 C -7.463417 2.564836 3.153048 C -6.288060 1.875363 3.474122 C -5.553417 1.272053 2.414573 S63

C -5.541793-1.514486 2.705268 C -4.260303-0.699019 2.700821 C -2.237801-0.443824 5.912339 C -0.237879 1.442250 7.206594 C -4.204035 4.965671 4.310096 C -5.239057 5.884905 4.109718 C -5.087211 7.211121 4.505356 C -3.895463 7.603383 5.121091 C -2.876935 6.680621 5.332045 C -2.999018 5.341652 4.910069 C 1.065530 4.524341 4.961579 C 2.227231 5.122167 4.480893 C 2.149607 6.180479 3.572240 C 0.896333 6.620666 3.149826 C -0.265707 6.005816 3.620618 C -0.207915 4.945322 4.538405 C -3.177191 1.880360 7.647379 C -1.991201 2.475643 4.754841 C 0.432339 3.374747 1.595884 C -4.315019 4.405687 0.910145 C -0.798575 3.963612 1.003276 C -0.872416 4.946500 0.002769 C -2.219614 5.158307-0.196680 C -1.204349 1.322140-1.750286 C -1.213803 0.131286-0.780255 C 1.461059-1.242567 4.367582 C 1.274634 0.152786 3.750431 C -0.960662-2.458521 2.028660 C -1.776058-1.208208 2.316855 C 1.282093 0.090490-0.575898 C 2.474162 0.067704 0.133439 C 2.436958 0.086785 1.521981 C 1.229769 0.107983 2.228564 C 0.017255 0.080583 1.494013 C 0.044343 0.100683 0.077004 H -4.510395 5.123648 1.709672 H -4.831786 4.709180-0.001785 H -4.691500 3.425713 1.203195 H -2.748605 5.839636-0.847855 H -0.046721 5.432013-0.494540 H 0.901969 2.661617 0.913083 H 1.147250 4.171944 1.815060 H -1.966097 6.997645 5.834851 H -3.766730 8.631450 5.451048 S64

H -5.890348 7.927325 4.353597 H -6.168553 5.555239 3.649476 H -4.339058 3.925038 4.022914 H -1.230040 6.369200 3.279157 H 0.818307 7.447682 2.447345 H 3.054076 6.663034 3.211024 H 3.196348 4.776611 4.832838 H 1.138729 3.723105 5.692448 H -1.491262-0.854723 5.225951 H -2.194007-1.025381 6.840755 H -3.223193-0.603523 5.465166 H -0.004260 2.460010 7.535904 H -0.274006 0.802377 8.096661 H 0.581112 1.089220 6.573785 H -2.979905 1.316613 8.567174 H -3.103843 2.946951 7.882281 H -4.204729 1.668130 7.340473 H 2.388389-1.704886 4.008798 H 1.522119-1.167655 5.458376 H 0.635079-1.916097 4.129705 H 2.323640 2.077576 3.809933 H 2.290526 1.207620 5.347924 H 3.380174 0.678643 4.075126 H 0.314528 0.554026 4.098673 H -0.383388 1.247007-2.471553 H -2.135775 1.355430-2.324009 H -1.095683 2.273895-1.222559 H -2.332298-1.142666-2.147820 H -0.578981-1.343054-2.261982 H -1.458129-2.044221-0.900577 H -2.071461 0.249010-0.109607 H 1.308066 0.091518-1.662523 H 3.426189 0.045286-0.390026 H 3.370835 0.086897 2.075135 H -4.108145 2.168860-0.806426 H -4.516930 0.950659-2.017912 H -5.718005 2.156010-1.547380 H -7.216428 0.048924-1.210139 H -5.868003-1.066583-1.444446 H -6.818757-1.117918 0.051129 H -4.550970 0.013769 0.302908 H -7.596085 2.613406 5.986054 H -6.067305 2.722257 6.850520 H -6.372786 3.807105 5.499461 S65

H -5.667486-0.453432 5.012244 H -6.013053 0.301016 6.563024 H -7.304203 0.131121 5.363919 H -4.793175 1.851897 4.998106 H -8.030428 3.036302 3.948100 H -8.850574 3.197787 1.632994 H -7.631452 2.043910-0.182883 H -1.110680-3.181946 2.835584 H -1.314620-2.933530 1.108146 H 0.104820-2.266601 1.918608 H -3.301453-2.553869 2.803038 H -6.433253-0.917805 2.892438 H -5.661498-2.017893 1.740646 H -5.475356-2.298290 3.465460 H 0.225903 2.873565 2.546222 125 Pyrazole s addition transition state (isomer) Sc -0.333150 0.727137 5.580427 P -1.710697-0.176466 2.263458 Si -2.446674-1.708485 4.616819 N -1.293020 1.291531 7.551623 N 2.029723 2.718093 3.856671 N 0.935909 2.309626 4.538650 N 1.204705-0.405202 6.814705 C -1.827042-3.282838 3.737912 C -2.294551-2.084417 6.480415 C 3.667138 2.558745 7.790078 C 2.135311-3.025638 3.369838 C 0.694563 4.833635 7.602207 C -5.026716 0.575094 7.822903 C -1.932156 0.816914 9.905387 C 1.792956-1.891027 8.729845 C 0.889891-0.898390 8.018339 C -0.246935-0.550452 8.767362 C -1.145414 0.523353 8.641298 C 0.486633 3.953972 9.956649 C 0.101067 3.726057 8.487764 C -5.108701 1.909964 5.698257 C -4.199029 1.400397 6.824879 C -1.406286 3.642908 8.289021 C -2.168534 4.772679 8.605073 C -3.541362 4.797905 8.410548 C -4.162123 3.693169 7.843132 S66