Vinyl-dimethylphenylsilanes as Safety Catch Silanols in Fluoride free Palladium Catalysed Cross Coupling Reactions. James C. Anderson,* Rachel H. Munday School of Chemistry, University of Nottingham, Nottingham, NG7 2RD, UK j.anderson@nottingham.ac.uk Index Page General experimental... S3 E-1-Iodo-5-phenylpent-1-ene (11)...S3 E-1-(Phenyldimethylsilyl)-5-phenylpent-1-ene (6).S3 Dimethylphenyl-(5-phenyl-pent-1-ynyl)silane (12) S3 Z-1-(Dimethylphenylsilyl)-5-phenylpent-1-ene (7) S4 E-1-Iodo,1-(phenyldimethylsilyl), 5-phenylpent-1-ene (13)... S4 2-(Dimethylphenylsilyl)-6-phenyl-E-hex-2-ene (8) S4 E-1-Iodo,1-(phenyldimethylsilyl)propene (15)....S5 3-(dimethylphenyl),6-phenyl-Z-hex-2-ene (9).S5 General procedure for cross coupling...s5 2,5-Diphenylpent-1-ene (5)..S5 E-1,5-Diphenylpent-1-ene (3)..S6 Z-1,5-Diphenylpent-1-ene S6 2,6-Diphenyl-E-hex-2-ene S6 3,6-Diphenyl-Z-hex-2-ene S6 2-(Dimethylsilanol)-5-phenylpent-1-ene (2).S7 5-Phenyl-1-pentene (4)..S7 S1
Copies of 1H and 13C NMR spectra: E-1-Iodo-5-phenylpent-1-ene (11) 1H..S8 13C....S9 E-1-(Phenyldimethylsilyl)-5-phenylpent-1-ene (6) 1H..S10 13C....S11 Dimethylphenyl-(5-phenyl-pent-1-ynyl)silane (12) 1H..S12 13C....S13 Z-1-(Dimethylphenylsilyl)-5-phenylpent-1-ene (7) 1H..S14 13C....S15 E-1-Iodo,1-(phenyldimethylsilyl), 5-phenylpent-1-ene (13) 1H..S16 13C....S17 2-(Dimethylphenylsilyl)-6-phenyl-E-hex-2-ene (8) 1H..S18 13C....S19 E-1-Iodo,1-(phenyldimethylsilyl)propene (15) 1H..S20 13C....S21 3-(dimethylphenyl),6-phenyl-Z-hex-2-ene (9) 1H..S22 13C....S23 2,5-Diphenylpent-1-ene (5) 1H..S24 13C....S25 Z-1,5-Diphenylpent-1-ene 2,6-Diphenyl-Z-hex-2-ene 3,6-Diphenyl-Z-hex-2-ene 1H..S26 13C....S27 1H..S28 13C....S29 1H..S30 13C....S31 2-(Dimethylsilanol)-5-phenylpent-1-ene (2) 1H..S32 13C....S33 5-Phenyl-1-pentene (4) 1H..S34 13C....S35 S2
General experimental. For all non-aqueous chemistry, except coupling reactions, glassware was rigorously flame-dried and an inert (N 2 ) atmosphere was maintained throughout. Thin layer chromatography was carried out on 60F silica-aluminium plates with potassium permanganate for visualization. For flash column chromatography, silica gel was used and direct column loading was employed in all cases. Unless stated otherwise, compound data shows good concordance with literature values. NMR data was collected at 400 or 500MHz. Data was manipulated directly from the spectrometer or via a networked PC with software. All samples were analysed in CDCl 3 unless otherwise stated. Reference values for residual solvent was taken as δ = 7.27 (CDCl 3 ) for 1 H-NMR; δ = 77.16 (CDCl 3 ) for 13 C-NMR. Multiplicities for coupled signals are denoted thus: s = singlet, d = doublet, t = triplet, q = quartet, m = multiplet. Coupling constants (J) are given in Hz. Mass spectrometric data was collected using CI/FAB and EI. The same equipment was used for high-resolution studies; results are quoted to four decimal places (0.1 mda) with error limits for acceptance of +/-5.0 ppm (defined as calcd./found mass 10-6 ). Infrared data was collected on sodium chloride discs. Both oils and solids were analysed neat. All solvents and reagents were used as supplied or purified using standard techniques. E-1-Iodo-5-phenylpent-1-ene (11). To a solution of 5-phenyl-1-pentyne (10) (1.09g, 7.55 mmol) stirred in a water bath was added DIBAL (8.3 ml of a 1 M solution in hexanes, 8.3 mmol) dropwise over 0.5 h. The reaction mixture was stirred at rt for 30 min then heated to 50 o C for 4 h. The reaction mixture was allowed to cool to rt and the hexanes removed under reduced pressure. The residue was cooled to 0 o C, THF (10 ml) was added and the mixture cooled to -78 o C. A solution of I 2 (2.29g, 9.06 mmol) in THF (5 ml) was added dropwise via cannula and the mixture was stirred at 0 o C for 0.5h. The mixture was transferred via cannula onto 6 M HCl (30 ml) and pentane (7 ml) stirred at 0 o C and extracted with petrol (2 x 20 ml). The combined organics were washed with 1 M NaOH (2 x 20 ml), 10 % aq. sodium sulfite (2 x 20 ml), brine (2 x 20 ml), dried (MgSO 4 ) and concentrated in vacuo. Purification by column chromatography (petrol) gave 11 as a colourless oil (1.15 g, 56 %) (> 90 % pure by 1H NMR). IR ν max (film) 3025, 2933, 1604 cm -1 ; 1 H NMR δ 1.78 (2H, quintet, J 7.7), 2.20 (2H, q, J 6.6), 2.66 (2H, t, J 7.7), 6.05 (1H, dt, J 14.3, 1.3), 6.58 (1H, quintet, J 7.1), 7.20-7.35 (5H, m); 13 C NMR δ 29.9, 35.1, 35.5, 75.0, 125.9, 128.4, 128.5, 141.8, 146.2; m/z (EI + ) HRMS C 11 H 13 I calcd. 272.0062, found 272.0064 (21%, M + ). E-1-(Phenyldimethylsilyl)-5-phenylpent-1-ene (6). To a solution of 11 (1.15 g, 4.23 mmol) in Et 2 O (40 ml) at -78 o C was added t BuLi (5.5 ml of a 1.7 M solution in hexanes, 9.3 mmol) dropwise. After 1 h PhMe 2 SiCl (0.64 ml, 3.8 mmol) was added and the mixture was allowed to warm to rt overnight with stirring. The mixture was quenched carefully with H 2 O (30 ml), extracted into Et 2 O (20mL) and washed with water (2 x 25 ml), brine (2 x 25 ml), dried (MgSO 4 ) and concentrated in vacuo. Purification by column chromatography (2% EtOAc/petrol) gave 6 as a colourless oil (0.85 g, 80 %) IR ν max (film) 3025, 2934, 1247 cm -1 ; 1 H NMR δ 0.34 (6H, s), 1.77 (2H, quintet, J 7.6), 2.22 (2H, q, J 6.7), 2.64 (2H, t, J 7.7), 5.80 (1H, dd, J 19.6, 1.3), 6.14 (1H, dt, J 18.4, 6.1), 7.18-7.54 (10H, m); 13 C NMR δ -2.2, 30.4, 35.5, 36.3, 125.6, 127.7, 128.0, 128.4, 128.5, 128.8, 133.9, 139.3, 142.5, 148.8; m/z (EI + ) 280 (43%, M + ), 265 (64%), 135 (100%); HRMS C 19 H 24 Si calcd. 280.1647, found 280.1639. Anal. calcd. for C 19 H 24 Si: C, 81.36; H, 8.62; found C, 81.27; H, 8.71 %. Dimethylphenyl-(5-phenyl-pent-1-ynyl)silane (12). To a solution of 5-phenyl-1-pentyne (10) (2.06 g, 14.2 mmol) in THF (50 ml) at 78 o C was added n BuLi (5.90 ml of a 2.4 M solution in hexanes, 14.2 mmol) dropwise over 5 min. After the mixture was stirred at -78 o C for 1.5 h PhMe 2 SiCl (2.30 ml, 14.2 mmol) was added and the mixture was allowed to warm to rt overnight with stirring. The mixture was quenched carefully with H 2 O (30 ml), extracted into Et 2 O (20 ml), washed with water (2 x 25 ml), brine (2 x 25 ml), dried (MgSO 4 ) and concentrated in vacuo. The residue was filtered through a plug of silica and eluted with petrol to give 12 as a colourless oil (3.1 S3
g, 84 %); IR ν max (film) 3025, 2945, 2174, 1249 cm -1 ; 1 H NMR δ 0.43 (6H, s), 1.88 (2H, quintet, J 7.5), 2.28 (2H, t, J 7.2), 2.75 (2H, t, J 7.6), 7.16-7.68 (10H, m); 13 C NMR δ -0.5, 19.5, 30.3, 34.8, 83.1, 109.1, 126.0, 127.9, 128.5, 128.6, 129.4, 133.8, 137.7, 141.6; m/z (EI + ) 278 (11%, M + ), 263 (100%); HRMS C 19 H 22 Si calcd. 278.1491, found 278.1500. Z-1-(Dimethylphenylsilyl)-5-phenylpent-1-ene (7). To a solution of 12 (1.24 g, 4.46 mmol) in Et 2 O (10 ml) was added DIBAL (0.88 ml, 4.9 mmol) dropwise at rt and the mixture heated at reflux for 4 h. The solution was cooled to 0 o C and NaOH (50 ml, 3 M solution) was added. The aqueous was extracted with petrol (3 x 30 ml) and the combined organics were washed with aq. NaOH (2 x 20 ml, 2 M solution), brine (2 x 20 ml), dried (MgSO 4 ) and concentrated in vacuo to give 7 as a colourless oil (1.22 g, 98%); IR ν max (film) 3025, 2958, 1248 cm -1 ; 1 H NMR δ 0.36 (6H, s), 1.63 (2H, quintet, J 7.7), 2.09 (2H, q, J 7.4), 2.50 (2H, t, J 7.8), 5.70 (1H, d, J 13.6), 6.46 (1H, dt, J 14.1, 7.1), 7.11-7.55 (10H, m); 13 C NMR δ -0.8, 31.4, 33.5, 35.6, 125.8, 127.3, 127.8, 128.3, 128.5, 128.9, 133.8, 139.8, 142.4, 150.3; m/z (EI + ) 280 (45%, M + ), 265 (64%); HRMS C 19 H 24 Si calcd. 280.1647, found 280.1642. E-1-Iodo,1-(dimethylphenylsilyl), 5-phenylpent-1-ene (13). To a solution of 12 (1.22 g, 4.39 mmol) in Et 2 O (11 ml) was added DIBAL (0.86 ml, 4.8 mmol) dropwise at rt and the solution heated at reflux for 4 h. The solution was cooled to 0 o C and I 2 (1.70 g, 6.60 mmol) in Et 2 O (40 ml) was added via cannula and the mixture allowed to warm to rt overnight with stirring. The mixture was transferred via cannula onto aq. HCl (40 ml of a 6 M solution) and petrol (20 ml) at 0 o C with stirring. The aqueous was extracted with petrol (2 x 20 ml), the combined organics washed with aq. NaOH (2 x 15 ml of a 1M solution), aq. sodium sulfite (2 x 15 ml of a 10% solution), brine (2 x 15 ml), dried (MgSO 4 ) and concentrated in vacuo. The residue was purified by column chromatography (petrol) to give 13 as a colourless oil (1.34 g, 75 %); IR ν max (film) 3025, 2929, 1250 cm -1 ; 1 H NMR δ 0.52 (6H, s), 1.55 (2H, quintet, J 7.7), 1.87 (2H, q, J 7.7), 2.39 (2H, t, J 7.7), 7.14-7.57 (11H, m); 13 C NMR δ 0.6, 30.5, 35.0, 35.2, 104.0, 125.9, 128.0, 128.3, 128.4, 129.5, 133.8, 137.6, 141.7, 157.7; m/z (EI + ) 406 (5%, M + ), 279 (17%); HRMS C 19 H 23 ISi calcd. 406.0614, found 406.0621. 2-(Dimethylphenylsilyl)-6-phenyl-E-hex-2-ene (8). To a solution of 13 (0.20 g, 0.50 mmol) in THF (3 ml) at -78 o C was added s BuLi (0.85 ml of a 1.3 M solution in hexanes, 1.1 mmol) dropwise and the solution stirred for 30 min. MeI (0.090 ml, 1.5 mmol) was added and the mixture was allowed to warm to rt overnight with stirring. After careful addition of H 2 O (3 ml) the aqueous was extracted with petrol (2 x 2 ml). The combined organics were washed with water (2 x 3 ml), brine (1 x 3 ml), dried (MgSO 4 ) and concentrated in vacuo to give 8 as a colourless oil (0.14 g, 97 %); IR ν max (film) 3025, 2949, 1248 cm -1 ; 1 H NMR δ 0.51 (6H, s), 1.68 (2H, quintet, J 7.7), 1.96 (3H, d, J 1.2), 2.13 (2H, q, J 7.6), 2.57 (2H, t, J 7.8), 6.26 (1H, td, J 7.5, 1.5), 7.20-7.66 (10H, m); 13 C NMR δ -1.0, 25.2, 31.7, 32.0, 35.6, 125.7, 127.8, 128.3, 128.4, 128.8, 132.9, 133.8, 139.7, 142.5, 143.9; m/z (EI + ) 294 (2%, M + ), 279 (11%); HRMS C 20 H 26 Si calcd. 294.1804, found 294.1790. Ph 4 3 SiMe 2 Ph 1 8 Irradiated Enhanced (%) H-3 H-4 H-1 H-1 (2.2), H-4 (1.5) SiMe 2 (0.9), PhCH 2 (1.1), H-3 (0.7) SiMe 2 (0.9), H-3 (0.7) E-1-Iodo,1-(dimethylphenylsilyl)propene (15). To a solution of 1-dimethylphenylsilylprop-1-yne (14) (0.39 g, 2.2 mmol) in Et 2 O (0.5 ml) at 0 o C was added DIBAL (0.44 ml, 2.5 mmol) dropwise S4
at rt and the solution heated at reflux for 4 h. The solution was cooled to 0 o C and I 2 (0.68 g, 2.7 mmol) in Et 2 O (30 ml) was added via cannula and the mixture allowed to warm to rt overnight with stirring. The mixture was transferred via cannula onto a stirred mixture of aq. HCl (30 ml of a 6 M solution) and petrol (10 ml) at 0 o C. The aqueous was extracted with petrol (2 x 20 ml) and the combined organics washed with aq. NaOH (2 x 15 ml of a 1 M solution), aq. sodium sulfite (2 x 15 ml of a 10% solution), brine (2 x 15 ml), dried (MgSO 4 ) and concentrated in vacuo. The residue was purified by column chromatography (petrol) to give 15 as a colourless oil (0.56 g, 83 %); IR ν max (film) 2956, 1250 cm -1 ; 1 H NMR δ 0.57 (6H, s), 1.56 (3H, d, J 6.7), 7.35-7.60 (6H, m); 13 C NMR δ 0.4, 21.3, 103.9, 127.8, 129.5, 133.9, 137.5, 152.6; m/z (EI + ) 301 (28%, M + ), 135 (100%); HRMS C 11 H 15 SiI calcd. 301.9988, found 301.9984. 3-(Dimethylphenylsilyl),6-phenyl-Z-hex-2-ene (9). To a solution of 15 (1.50 g, 5.00 mmol) in THF (20 ml) at -78 o C was added s BuLi (7.8 ml of a 1.4 M solution in hexanes, 11 mmol) dropwise over 5 min and the reaction stirred for 5 min. HMPA (2 ml) was added rapidly and the reaction stirred for a further 20 min. A solution of 1-iodo-3-phenylpropane (2.44 g, 9.90 mmol) in THF (5 ml + 2 ml wash) was added slowly via cannula and the reaction mixture allowed to warm to rt overnight with stirring. After careful addition of H 2 O (10 ml) the aqueous was extracted with petrol (2 x 10 ml). The combined organics were washed with H 2 O (4 x 10 ml), brine (1 x 10 ml), dried (MgSO 4 ), filtered through a silica plug and concentrated in vacuo. The residue was purified by column chromatography (petrol) to give 9 as a colourless oil (1.22 g, 84 %); IR ν max (film) 3025, 2932, 1247 cm -1 ; 1 H NMR δ 0.35 (6H, s), 1.56 (2H, quintet, J 8.0), 1.70 (3H, d, J 6.7), 2.19 (2H, t, J 8.1), 2.55 (2H, t, J 7.7), 5.97 (1H, q, J 6.5), 7.08-7.53 (10H, m); 13 C NMR δ -2.6, 14.6, 29.2, 31.4, 36.2, 125.7, 127.7, 128.3, 128.4, 128.8, 134.1, 136.7, 139.3, 139.9, 142.6; m/z (EI + ) 294 (7%, M + ), 216 (70%); HRMS C 20 H 26 Si calcd. 294.1804, found 294.1807. 1 4 2 Ph SiMe 2 Ph Irradiated Enhanced (%) 9 H-2 H-1 H-4 SiMe 2 (1.5), H-1 (1.9) SiMe 2 (0.1), H-2 (0.9), H-4 (0.9) SiMe 2 (0.7), H-1 (1.4) General procedure for cross coupling. To a solution of silane (0.20 mmol) in reagent grade THF (1.5 ml) was added KOTMS (2.0 equiv.) and 18-C-6 (2.0 equiv.) at rt and the solution stirred for 30 min. PhI (1.1 equiv.) was added and after a further 10 min Pd 2 dba 3 (5 mol%) was added and the mixture heated at reflux for 2 h. The reaction mixture was purified by filtering through a silica plug and eluting with Et 2 O, column chromatography (petrol) and where necessary bulb to bulb distillation to give the coupled product. 2,5-Diphenylpent-1-ene (5). Prepared using general procedure above, silane 1 (60 mg, 0.21 mmol) gave 5 as a colourless oil (41 mg, 86 %) after purification by column chromatography (petrol). IR ν max (film) 3025, 2936, 2857, 1601, 1495 cm -1 ; 1 H NMR δ 1.84 (2H, quin, J = 7.7), 2.58 (2H, t, J = 7.6), 2.70 (2H, t, J = 7.8), 5.11 (1H, q, J = 1.4), 5.32 (1H, d, J = 1.5), 7.18-7.54 (10H, m); 13 C NMR δ 30.0, 34.9, 35.5, 112.5, 125.8, 126.2, 127.4, 128.4, 128.5; m/z (EI + ) HRMS C 17 H 18 calcd. 222.1409, found 222.1403 (31%, M + ). E-1,5-Diphenylpent-1-ene (3). Prepared using general procedure above, silane 6 (51 mg, 0.18 mmol) gave 3 as a colourless oil (33 mg, 82 %) after purification by column chromatography (petrol). 13 S5
Z-1,5-Diphenylpent-1-ene. Prepared using general procedure above, silane 7 (293 mg, 1.05 mmol) gave Z-1,5 diphenylpent-1-ene as a colourless oil (144 mg, 62 %) after purification by column chromatography (petrol). IR ν max (film) 3025, 2926, 2856, 1601, 1494 cm -1 ; 1 H NMR δ 1.83 (2H, quintet, J 7.6), 2.41 (q, J 7.4), 2.68 (2H, t, J 7.7), 5.73 (1H, dt, J 11.6, 7.3), 6.48 (1H, d, J 11.6), 7.17-7.36 (10H, m); 13 C NMR δ 28.2, 31.8, 35.6, 125.8, 126.6, 128.2, 128.4, 128.5, 128.8, 129.3, 132.6, 137.7, 142.4; m/z (EI + ) 222, (70%, M + ), 131 (100%); HRMS C 17 H 18 requires 222.1409, found 222.1401. Ph 3 2 Ph 1 Irradiated Enhanced (%) H-1 H-2 H-3 H-2 (2.1), Ph (0.8) H-1 (2.5), H-3 (0.9) H-2 (0.5), Ph (1.3) 2,6-Diphenyl-Z-hex-2-ene. Prepared using general procedure above, silane 8 (186 mg, 0.788 mmol) gave 2,6-diphenyl-E-hex-2-ene as a colourless oil (100 mg, 67 %) after purification by column chromatography (petrol) and then Kugelrohr distillation bp. 127 C (0.05 mm). IR ν max (film) 3025, 2929, 1600, 1494 cm -1 ; 1 H NMR δ 1.67 (2H, quintet, J 7.6), 2.05 (5H, m), 2.58 (2H, t, J 7.8), 5.52 (1H, t, J 6.6), 7.13-7.37 (10H, m); 13 C NMR δ 25.7, 28.8, 32.0, 35.5, 125.7, 126.5, 127.1, 128.0, 128.1, 128.3, 128.5, 136.6, 142.2, 142.7; m/z (EI + ) HRMS C 18 H 20 requires 236.1565, found 236.1568. Ph 4 Ph 1 3 Irradiated Enhanced (%) H-3 H-1 (2.6) Cannot irradiate H-1 and H-4 due to overlapping signals 3,6-Diphenyl-Z-hex-2-ene. Prepared using general procedure above, except that reaction stirred at reflux for 30 min before the addition of PhI and Pd 2 dba 3, silane 9 (335 mg, 1.14 mmol) gave 3,6- diphenyl-z-hex-2-ene as a colourless oil (204 mg, 76 %) after purification by column chromatography (petrol) and then Kugelrohr distillation bp. 105 C (0.02 mm). IR ν max (film) 3026, 2931, 1601, 1496 cm -1 ; 1 H NMR δ 1.65 (2H, quintet, J 7.8), 1.73 (2H, d, J 6.9), 2.52 (2H, t, J 7.7), 2.58 (2H, t, J 7.8), 5.73 (1H, q, J 6.9), 7.09-7.27 (10H, m); 13 C NMR δ 14.2, 29.1, 30.1, 35.7, 123.2, 125.7, 126.3, 126.5, 128.2, 128.3, 128.5, 140.7, 142.4, 143.4; m/z (EI + ) 236 (30%, M + ), 132 (100%); HRMS C 18 H 20 requires 236.1565, found 236.1568. Ph 4 Ph 1 2 Irradiated Enhanced (%) H-2 H-1 H-4 Ph (1.4), H-1 (1.0) H-2 (0.5) Ph (0.7), H-1 (1.2) S6
2-(Dimethylsilanol)-5-phenylpent-1-ene (2). To a solution of 2-iodo-5-phenylpent-1-ene (2.20 g, 8.09 mmol) in Et 2 O (40 ml) at 78 o C was added t BuLi (10.5 ml of a 1.7 M solution in hexanes, 17.8 mmol) dropwise over 5 min. After the mixture was stirred at 78 o C for 1.5 h (Me 2 SiO) 3 (0.54 g, 2.4 mmol) in Et 2 O (5 ml) was added via cannula and the mixture allowed to warm to rt overnight with stirring. The mixture was quenched carefully with water (20 ml) and extracted into Et 2 O (2 x 20 ml). The combined organics were washed with water (2 x 20 ml), brine (2 x 20 ml), dried (MgSO 4 ) and concentrated in vacuo to give 2 as a colourless oil (1.47 g, 92 %). IR ν max (film) 3296, 3027, 2936, 1603, 1252 cm -1 ; 1 H NMR δ 0.22 (6H, s), 1.60 (1H, bs), 1.77-1.82 (2H, m), 2.18-2.26 (2H, t, J = 7.6), 2.59-2.65 (2H, t, J = 7.7), 5.47-5.49 (1H, dt, J = 2.8, 1.1), 5.62-5.64 (1H, dt, J = 3.1, 1.5), 7.19-7.63 (5H, m); 13 C NMR δ -0.2, 30.8, 35.2, 35.8, 125.6, 125.8, 128.4, 128.5, 142.5, 151.3; m/z (EI + ) HRMS C 13 H 20 OSi requires 220.1283, found 220.1274 (8%, M + ). 5-Phenyl-1-pentene (4). IR ν max (film) 2961, 2932, 1641 cm -1 ; 1 H NMR δ 1.73 (2H, quin, J = 7.6), 2.10 (2H, t, J = 7.2), 2.64 (2H, t, J = 7.6), 4.97-5.06 (2H, m), 5.81-5.89 (1H, m), 7.18-7.30 (5H, m); 13 C NMR δ 30.7, 33.4, 35.4, 114.8, 125.8, 128.4, 128.6, 138.7, 142.5; m/z (EI + ) HRMS C 11 H 14 calcd. 146.1096, found 146.1100 (60%, M + ). S7
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