The dramatic effect of Lewis acids on the outcome of rhodium-catalyzed hydroborations. Contents

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1 S-1 The dramatic effect of Lewis acids on the outcome of rhodium-catalyzed hydroborations SUPPLEMENTARY INFRMATIN Christopher J. Lata and Cathleen M. Crudden* Department of Chemistry, Queen s University, 90 Bader Lane, Kingston ntario Canada K7L 3N6 Contents Synthetic Procedures S-2 Table S-1, Data for Figure S-1 S-5 NMR Study 1 uter sphere Lewis acid-catalyst interaction study S-6 Figure S-1a, 31 P-NMR study of [Rh(CD)(DPPB)]BF 4 and FAB in a 1:1 mixture. S-6 Figure S-1b, verlay of 19 F-NMR spectra of [Rh(CD)(DPPB)]BF 4, FAB and both in a 1:1 mixture. S-7 Figure S-1c, Expanded 19 F spectrum of [Rh(CD)(DPPB)]BF 4 S-8 Figure S-1d-e, 19 F spectra of FAB S-9 Figure S-1f-h (S-2), 1:1 Mixture of FAB and Rh catalyst ( 19 F spectra) S-11 NMR Study 1 relevant peak listing S-15 Figure S-3a-b, 31 P spectra for Rh catalyst in presence of FAB S-15 Figure S-4a, 1 H spectrum of [Rh(CD)(DPPB)]BF 4 THF S-17 Figure S-4b-e, 11 B spectra of HBPin activation under various conditions S-18 Figure S-5a, Hydroboration of allylbenzene in the absence of Lewis acid S-20 Figure S-5b, Hydroboration of allylbenzene in the presence of Lewis acid S-20 References S-21 Synthetic Procedures

2 S-2 General. Unless otherwise noted, all reactions were undertaken in an inert (Nitrogen) atmosphere in a glovebox using dried glassware. Reaction solvents were all dried according to the literature and de-oxygenated via a minimum of three freeze-pump-thaw cycles before storage under nitrogen. As precaution, all solvents were stored over 4 angstrom molecular sieves to remove trace moisture. All reagent olefins used were purified via bulb-to-bulb distillation followed by a minimum of three freeze-pump-thaw cycles to remove oxygen before storage at -20 o C under nitrogen in the glovebox. 4,4,5,5-tetramethyl-1,3,2-dioxoborolane (HBPin) was purchased from Aldrich, distilled and de-oxygenated as above, and also stored in the glovebox at -20 o C. Lewis acids employed were obtained from Aldrich and Strem and were brought into the glovebox sealed and used as purchased. B(C 6 F 5 ) 3 (CAS Registry No.: ) is referred to as FAB in most cases, but in several NMR spectra, as the acronym BARF is used. All NMR spectra were obtained on 300-, 400-, and 500-MHz Bruker Avance spectrometers. All GC spectra were obtained using an Agilent 6850 chromatograph loaded with an HP-5 column (L=30metres; ID= 0.32mm) and operating with splitless injection (He carrier gas). All samples analyzed by GC were done so with the following methodology: Initial Temp. = 80 o C (held for 6min.); Rate = 10 o C/min; Final Temp. = 220 o C. Synthesis of [rhodium(1,4-cyclooctadiene)(bis-diphenylphosphinobutane)] tetrafluoroborate (1) and hexafluoroantimonate (2) analogue (THF-bound) [Rh(CD)Cl] 2 (300.4mg, 0.61mmol) was charged to a flame-dried Schlenk flask under argon. Atmosphere was removed and re-filled 3 times to remove trace oxygen. Via cannula, 5mL of THF was added to the flask to dissolve the solid and was stirred. All THF was freshly degassed as noted above and was dried over 4 angstrom molecular sieves before use. AgBF 4 (241.4mg, 1.24mmol) or AgSbF 6 (412mg, 1.22mmol), depending on which anion was desired, was charged to dry RBF flask in the glovebox, then removed sealed and placed under argon. THF was added to solvate the salt in the same manner. The AgBF 4 solution was cannulated into the Schlench flask, causing precipitates to form. The solution was stirred for 2 hours. The filtrate was transferred via cannula filter into a second dry Schlenck containing DPPB (519.3mg, 1.22mmol) in THF, causing the solution to turn red. Red-orange crystals formed over time. Solvent removed to roughly 2mL under vacuum. The remaining liquid was removed by syringe. The crystals were washed once with 2mL of THF, dried under vacuum and brought into the box to be stored in fridge. Rh + BF 4 - : 31 P{ 1 H}-NMR: ppm(d, J 143 Hz). 19 F-NMR: (s, int = 1.00), (s, int = 0.25) General Hydroboration Procedure All reactions were set up in a nitrogen glovebox in dry disposable glass vials fitted with Teflon seal screw caps. A 4-dram glass vial was charged with 1 (1mol%) and FAB (2mol%) and 2mL of DCE was added. The vial was then sealed and agitated until solids had dissolved. A separate 1-dram vial was charged with dodecane internal standard (unless isolated yields were desired, in which case the internal standard was omitted), trans-4-octene (1mmol), and HBPin (1mmol). This solution was added with excess DCE to the catalyst/lewis acid solution for a total reaction volume of 4mL. 4,4,5,5-Tetramethyl-2-(1-propyl-pentyl)-[1,3,2]dioxaborolane. Synthesized as described above: (E)-4-octene (112mg, 1.0mmol), HBPin(128mg, 1.0mmol), 1 (7.8mg, 1.0mol%), FAB

3 S-3 (10.2mg, 2.0mol%), DCE (4mL), C for 8 hours. Reaction worked up to yield colourless oil. 13 C-NMR (CDCl 3 ): δ 82.8, 33.8, 31.6, 31.1, 24.8, 23.0, 22.4, 14.5, HRMS calcd. for C 14 H 29 B 2 (M+): ; found: B 2-Cyclooctyl-4,4,5,5-tetramethyl-[1,3,2]dioxaborolane. Synthesized as described above: cyclooctene (110mg, 1.0mmol), HBPin (128mg, 1.0mmol), 1 (7.6mg, 1.0mol%), FAB (10.0mg, 2.0mol%), DCE (4mL), 30 o C for 3 hours. Colourless oil isolated in 90% yield. 13 C-NMR (CDCl 3 ): δ 82.8, 27.6, 27.0, 26.9, 26.7, HRMS calcd. for C 14 H 27 B 2 (M+): ; found: B 4,4,5,5-Tetramethyl-2-(3-phenyl-propyl)-[1,3,2]dioxaborolane. Synthesized as described above: allylbenzene (117mg, 1.0mmol), HBPin (139mg, 1.1mmol), 1 (7.0mg, 1.0mol%), FAB (11.0mg, 2.3mol%), DCE (4mL), 70 o C for 7 hours. 1 H-NMR (CDCl 3 ): 0.85 (t, 2H, J 7.9 Hz), 1.27 (s, 12H), 1.76 (quintet, 2H, J 7.9 Hz), 2.63 (t, 2H, J 7.9 Hz) 7.20 (m, 3H), 7.28 (dd, 2H, J 10.3, 4.6 Hz). 13 C-NMR (CDCl 3 ): δ 24.9, 26.1, 38.6, 83.0, 125.6, , , 128.4, 128.6, HRMS calcd. for C 15 H 23 B 2 (M+): ; found: B

4 S-4 4,4,5,5-Tetramethyl-2-(1-phenyl-propyl)-[1,3,2]dioxaborolane. Synthesis as described above: beta-methylstyrene (130mg, 1.10mmol), HBPin (187mg, 1.46mmol), 1 (7.5mg, 0.9mol%), FAB (10.5mg, 1.8mol%), DCE (4mL), 70 o C for 9 hours. Colourless oil isolated in 84% yield. 1 H-NMR (CD 2 Cl 2 ): δ 0.80 (t, 3H, J 7.3 Hz), 1.10 (s, 6H), 1.12 (s, 6H), 1.55 (m, 1H), 1.76 (m,1h), 2.09 (t, 1H, J 7.8 Hz), (m, 3H), (m, 2H). 13 C-NMR (CD 2 Cl 2 ): δ 14.0, 24.8, 24.9, 26.1, 83.6, 125.8, 128.6, 128.8, HRMS calcd. for C 15 H 23 B 2 (M+): ; found: B 4,4,5,5-Tetramethyl-2-(2-methyl-pentyl)-[1,3,2]dioxaborolane. Synthesized as described above: 2-methyl-2-pentene (90mg, 1.1mmol), HBPin (131mg, 1.02mmol), 1 (7.2mg, 1.0mol%), FAB (10.3mg, 2.0mol%), DCE (4mL), 30 o C for 3 hours. Colourless oil isolated in 84% yield. 1 H- NMR (CDCl 3 ): δ 0.56 (dd, 1H, J 15.3, 8.4 Hz), 0.76 (dd, 1H, J 15.3, 5.8 Hz), 0.80 (t, 3H, J 7.1Hz), 0.83 (d, 3H, J 6.6 Hz), 1.09 (m, 2H det. by CSY), 1.18 (s, 12H), 1.25 (m, 2H det. by CSY), 1.63 (dq, 1H, J 6.5, 13.2 Hz). 13 C-NMR (CDCl 3 ): δ 14.3, 20.4, 22.3, 24.8, 24.9, 29.2, 42.0, HRMS calcd. for C 12 H 25 B 2 (M+): ; found: B 4,4,5,5-Tetramethyl-2-(2-phenyl-propyl)-[1,3,2]dioxaborolane. Synthesized as described above: α-methylstyrene (115mg, 1mmol), HBPin (141mg, 1.1mmol), 1 (7.3mg, 1.0mol%), FAB (11.2mg, 2.2mol%), DCE (4mL), 70 o C for 9 hours. Colourless oil isolated in 87% yield. 1 H NMR (CD 2 Cl 2 ): δ 1.02 (d, 2H, J 7.6 Hz), 1.09 (s, 12H), 1.20 (d, 3H, J 6.9 Hz), 2.96 (m, 1H), (m, 1H), (m, 4H). 13 C-NMR (CDCl 3 ): δ 24.7, 24.8, 24.9, 35.8, 83.0, 125.5, 125.7, 126.6, 128.2, HRMS calcd. for C 15 H 23 B 2 (M+): ; found: B

5 S-5 Table S-1: Data used to generate Figure S-1, including yields a Additive/solvent 4-isomer 3-isomer 2-isomer 1-isomer Total yield THF b SbF La(Tf) Y(Tf) Zn(Tf) AlCl Sc(Tf) B(C 6 F 5 ) B(C 6 F 5 ) 3 [-20 0 C] a Note in some cases the Lewis acids showed very poor solubility, which may be responsible for the low yields noted. b - [Rh(CD)(DPPB)]SbF 6 catalyst employed rather than the BF 4 analogue

6 S-6 NMR Study 1 uter Sphere Lewis acid-catalyst Interaction Figure S-1a. 31 P-NMR spectrum (400MHz) of [Rh(CD)(DPPB)]BF 4 THF was found to be unchanged upon addition of FAB in DCE solvent. Spectra were calibrated to H 3 P 4 external standard. [Rh(CD)(DPPB)]BF J = 143 Hz 1:1 Rh + catalyst and FAB J = 143 Hz ppm (t1) F-NMR allowed the observation of a 1:1 interaction between FAB and 1 which can be interpreted as occurring via outer sphere binding of the BF 4 - counterion of the Rh catalyst (fluorine bridging) or by a reversible transfer of F from BF 4 to FAB. If complete transfer is observed, it is reversible, as shown by the remaining interaction of the fluorine in question with the BF 3 unit by 19 F NMR NESY and CSY spectroscopy. Previously reported fluorine shifts for both FB(C 6 F 5 ) 3 - and proposed fluorine-bridged boranes are quite similar 1,2, precluding delineation between the two binding modes, Although 19 F shifts are highly solvent dependent, making comparison to literature difficult, several related intramolecular fluorine bridges have been observed by NMR 3,4,5 and were found to resonate highly upfield. In addition, this interaction is supported by the upfield shift of all relevant fluorine peaks, as well as a splitting of the fluorine signal for the BF 4 - counterion (due to non-equivalency of the bound versus nonbound fluorine moieties). A greater upfield shift of meta and para signals relative to the ortho is indicative of adduct formation. verlay of 1D 19 F-NMR shows upfield shift for all relevant species. All solutions were made in DCE and calibrated against an external standard of CFCl 3. Detailed 19 F spectra are shown below, with additional 2-dimensional plots for relevant compounds and mixtures. The complex between catalyst and Lewis acid was formed in DCE with [Rh(CD)(DPPB)]BF 4 THF (14.24mg, 0.02mmol) and FAB (12.17mg, 0.024mmol). Additionally, the 11 B-NMR showed a marked upfield shift and peak sharpening for FAB in the presence of equimolar 1 (Figure S-1h; S-4d). See below.

7 S-7 Figure S-1b. 19 F-NMR spectrum of [Rh(CD)(DPPB)]BF 4 THF itself, FAB itself, and a 1:1 mixture in DCE solvent. Spectra were calibrated to CFCl 3 external standard. [Rh(CD)(DPPB)]BF 4 THF FAB ortho-f meta-f para-f 1:1 Mix Rh + and FAB ortho-f F 3 B---F para-f meta-f bridging F ppm (t1)

8 Figure S-1c 19 F-NMR of [Rh(CD)(DPPB)]BF 4 THF (integration matches natural abundance ratio of 10 B and 11 B) S-8

9 Figure S-1d 19 F-NMR of FAB S-9

10 Figure S-1e 19 F-CSY of FAB. S-10

11 Figure S-1f 19 F-NMR of equimolar mixture of [Rh(CD)(DPPB)]BF 4 THF and FAB. S-11

12 S-12 Figure S-1g 19 F-CSY of equimolar mixture of [Rh(CD)(DPPB)]BF 4 THF and FAB. bridging-f ortho-f

13 S-13 Figure S-1h 11 B-NMR of 1:1 complex of FAB and [Rh(CD)(DPPB)]BF 4 THF complexed FAB

14 S-14 Figure S-2 19 F-NESY of equimolar mixture of [Rh(CD)(DPPB)]BF 4 THF and FAB. F 3 B----F bridging-f

15 S-15 Relevant Peak Listings (Bruker Avance 400 MHz): FAB (in DCE). 19 F-NMR: (s, 6F), (s, broad, 3F), (s, broad, 6F) 1:1 FAB and [Rh(CD)(DPPB)]BF 4 THF (in DCE). 19 F-NMR: (s, broad, 6F), (s, 0.6F, 10 B isotopic signal), (s, 2.3F, 11 B isotopic signal), (t, J 20.1Hz, 3F), (t, broad, J 19.1 Hz, 6F), (s, broad, 1F). 2D-F-CSY: (-167.2), (-167.2), (-135.9, ). 2D-F-NESY(mix=0.4): (-191.6). Figure S-3 verlay of 31 P-NMR{ 1 H} Spectra of [Rh(CD)(DPPB)]BF 4 THF (0.01mmol) in DCE after warming indicating the presence of additional signals in the 40 ppm region

16 Figure S-3b Spectrum of [Rh(CD)(DPPB)]BF 4 THF ( 31 P{ 1 H}-NMR 400MHz) S-16

17 S-17 Figure S-4a 1 H-NMR of [Rh(CD)(DPPB)]BF 4 THF; 500MHz (d 2 -DCM, d1=25s) Figure S-4b verlay of 11 B-NMR of FAB and HBPin (10equiv.) in the presence and absence of THF (400MHz). Signals at ca. 20 ppm are indicative of decomposition of HBPin as these reactions were not cooled.

18 S-18

19 S-19 Figure S-4c verlay of 11 B-NMR of [Rh(CD)(DPPB)]BF 4 THF and THF-free version with FAB and H(D)BPin (400MHz) A THF-free [Rh(CD)(DPPB)]BF 4 (10 eq. HBPin); B [Rh(CD)(DPPB)]BF 4 THF (20 eq. HBPin); C - Rh(CD)(DPPB)]BF 4 THF (10 eq. DBPin) All spectra obtained at ambient tempareature B 2 Pin 3 A HBPin B [HB(C 6 F 5 ) 3 ] - DBPin C [DB(C 6 F 5 ) 3 ] -

20 S-20 Figure S-5a Hydroboration of allylbenzene with HBPin and DBPin in the absence of Lewis acid 0.4 Hydroboration of allyl benzene without Lewis acid HBPin DBPin Time (hours) Figure S-5b Hydroboration of allylbenzene with HBPin and DBPin in the presence of Lewis acid Hydroboration of allylbenzene in the presence of Lewis acid 25 deg.c HBPin DBPin Time (hours) References:

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