Electrophilic Borylation of Terminal Alkenes with BBr 3 /2,6-Disubstituted Pyridines

Transcription

1 Supporting Information Electrophilic Borylation of Terminal Alkenes with BBr 3 /2,6-Disubstituted Pyridines Shinya Tanaka,* Yuki Saito, Takaya Yamamoto, Tetsutaro Hattori * Department of Biomolecular Engineering, Graduate School of Engineering, Tohoku University, Aramaki-Aoba, Aoba-ku, Sendai , Japan S1

2 Contents: 1. Supplemental Tables and Figures... S3 2. General Information... S5 3. Preparation of Alkenes... S5 4. Borylation of Alkenes... S Typical procedure for the borylation of α,α diarylalkenes... S Typical procedure for the borylation of other alkenes... S7 5. References... S H, 13 C, and 11 B NMR Spectral Charts for Compounds Synthesized... S ,1'-Ethenylidenebis(4-methylbenzene) (1c)... S ,1'-Ethenylidenebis(4-chlorobenzene) (1d)... S tert-butyl(hex-5-en-1-yloxy)diphenylsilane (1k)... S (2,2-Diphenylvinyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (2a)... S ,4,5,5-tetramethyl-2-(2-phenylprop-1-en-1-yl)-1,3,2-dioxaborolane (2b)... S (2,2-Di-p-tolylvinyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (2c)... S (2,2-Bis(4-chlorophenyl)vinyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (2d)... S (E)-4,4,5,5-Tetramethyl-2-styryl-1,3,2-dioxaborolane (2f)... S (E)-4,4,5,5-Tetramethyl-2-(3-phenylprop-1-en-1-yl)-1,3,2-dioxaborolane (2g)... S (E)-2-(Hex-1-en-1-yl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (2h)... S (E)-4,4,5,5-Tetramethyl-2-(oct-1-en-1-yl)-1,3,2-dioxaborolane (2i)... S (E)-2-(6-Bromohex-1-en-1-yl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (2j)... S (E)-tert-Butyldiphenyl((6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hex-5-en- 1-yl)oxy)silane (2k)... S (2-Ethylbut-1-en-1-yl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (2l)... S (S)-4,4,5,5-Tetramethyl-2-(2-(4-methylcyclohex-3-en-1-yl)prop-1-en-1-yl)-1,3,2- dioxaborolane (2n)... S Methyl-3-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-indole (1o)... S ,4,5,5-Tetramethyl-2-(5-methylthiophen-2-yl)-1,3,2-dioxaborolane (1p)... S59 S2

3 1. Supplemental Tables and Figures Table S1. Borylation of ethene-1,1-diyldibenzene (1a) with various amount of BBr 3 and 2,6-dichloropyridine (B3). a entry x y 2a (%) b 1a (%) b n.d. n.d c a Reaction conditions: 1a (0.50 mmol), BBr 3 (x molar equiv, used as a 1.0 M CH 2 Cl 2 solution), B3 (y molar equiv), CH 2 Cl 2 (1.0 ml), 0 C, 24 h, then pinacol (3.0 molar equiv), Et 3 N (15 molar equiv), rt, 1 h. b Determined by 1 H NMR analysis using CH 2 Br 2 as the internal standard. c Pinacol (4.0 equiv) was used. Table S2. Borylation of ethene-1,1-diyldibenzene (1a) with BCl 3 and various pyridines. a entry Base 2a (%) b 1a (%) b 1 B1 n.d. quant. 2 B2 n.d B3 n.d B B5 n.d B6 n.d. 77 a Reaction conditions: 1a (0.50 mmol), BBr 3 (3.0 molar equiv, used as a 1.0 M CH 2 Cl 2 solution), base (3.0 molar equiv), CH 2 Cl 2 (1.0 ml), 0 C, 24 h, then pinacol (3.0 molar equiv), Et 3 N (15 molar equiv), rt, 1 h. b Determined by 1 H NMR analysis using CH 2 Br 2 as the internal standard. S3

4 Table S3. Borylation of prop-1-en-2-ylbenzene (1a) using various amount of BBr 3 and 2,6-lutidine (B5). a entry x yield (E/Z) b (60/40) (61/39) (64/36) 4 c (78/22) 5 d (68/32) 6 e (63/37) a Reaction conditions: 1b (0.50 mmol), BBr 3 (x molar equiv, used as a 1.0 M CH 2 Cl 2 solution), B5 (y molar equiv), CH 2 Cl 2 (1.0 ml), 0 C, 24 h, then pinacol (3.0 molar equiv), Et 3 N (15 molar equiv), rt, 1 h. b Determined by 1 H NMR analysis using CH 2 Br 2 as the internal standard. c Pinacol (4.0 equiv) was used. d Pinacol (5.0 equiv) was used. e Pinacol (6.0 equiv) was used. (a) (b) PP Figure S1. 1 H NMR spectra of (a) a 1:1 mixture of BBr 3 and 2,6-dichloropyridine (B3) and (b) B3 in CD 2 Cl 2. S4

5 2. General Information Melting points were taken with a micro melting point apparatus and are uncorrected. 1 H and 13 C NMR spectra were measured with tetramethylsilane as an internal standard and CDCl 3 as a solvent unless otherwise noted. Silica gel 60GF 254 was used for TLC. Silica gel columns were prepared by use of Silica gel 60 ( µm). The boric acid impregnated silica gel which was prepared according to the literature procedure was used for purification of boronic esters otherwise noted, because the boronic esters easily undergo protodeboronation during the purification on silica gel. 1 Water- and air-sensitive reactions were routinely carried out under nitrogen. Toluene was distilled from sodium diphenyl ketyl. Dichloromethane was distilled from calcium hydride. 3. Preparation of alkenes Commercially available alkenes 1a b, 1e j, and 1l p were used as purchased Preparation of 1c and 1d To a mixture of magnesium turnings (588 mg, 24 mmol) and dry diethyl ether (10 ml) was added a few drops of 1,2-dibromoethane, and the mixture was stirred for 10 min. After added a solution of 4-bromotoluene (d 1.40; 2.93 ml, 24 mmol) in dry diethyl ether (30 ml) dropwise at room temperature, the mixture was refluxed for 30 min. The mixture was cooled to 0 C, added 4-methylacetophenone (d 1.01; 2.66 ml, 20 mmol) dropwise, and the resulting mixture was stirred at room temperature for a further 30 min. The reaction was quenched with 2 M HCl, and the mixture was extracted with diethyl ether. The extract was dried over MgSO 4, and evaporated to leave a residue, which was dissolved by the addition of methanol (20 ml). To the solution was added concd HCl (1.0 ml), and the mixture was refluxed for 3 h. The reaction mixture was poured into water (10 ml), and extracted with hexane. The extract was dried over MgSO 4 and evaporated to leave a residue, which was purified by column chromatography on silica gel with hexane as the eluent to give alkene 1c. Alkene 1d was prepared by a similar procedure. S5

6 1,1'-Ethenylidenebis(4-methylbenzene) (1c) 2 A colorless powder; 1 H NMR (400 MHz) δ 2.32 (s, 6H), 5.36 (s, 2H), 7.09 (d, J = 8.0 Hz, 4H), (m, 4H); 13 C NMR (100 MHz) δ 21.3, 113.1, 128.3, 128.9, 137.5, 138.9, ,1'-Ethenylidenebis(4-chlorobenzene) (1d) 3 A colorless powder; 1 H NMR (400 MHz) δ 5.44 (s, 2H), (m, 4H), (m, 4H); 13 C NMR (100 MHz) δ 115.2, 128.6, 129.6, 134.0, 139.6, Preparation of 1k This compound was prepared according to the literature procedure. 4 tert-butyl(hex-5-en-1-yloxy)diphenylsilane (1k) 5 A colorless oil; 1 H NMR (400 MHz) δ 1.05 (s, 9H), 1.47 (quint, J = 7.6 Hz, 2H), 1.58 (quint, J = 6.8 Hz, 2H), 2.03 (dt, J = 7.2, 6.8 Hz, 2H), 3.66 (t, J = 6.4 Hz, 2H), (m, 2H), 5.79 (ddt, J = 17.0, 10.2, 6.7 Hz, 1H), (m, 6H), (m, 4H); 13 C NMR (100 MHz) δ 19.4, 25.3, 27.0, 32.2, 33.6, 64.9, 114.5, 127.7, 129.7, 134.3, 135.7, S6

7 4. Borylation of alkenes 4.1. Typical procedure for the borylation of α,α diarylalkenes (entry 9 in Table 1) Ph Ph 1a BBr 3 (3.0 equiv.) B3 (3.0 equiv.) CH 2 Cl 2, 0 C, 24 h pinacol (3.0 equiv.) ipr 2 NEt (15 equiv.) rt, 1 h To a solution of 2,6-dichloropyridine (B3) (222 mg, 1.50 mmol) in dichloromethane (0.5 ml) in a 10 ml test tube, were added BBr 3 (1.0 M solution in dichloromethane; 1.5 ml, 1.5 mmol), ethene-1,1-diyldibenzene (1a) (90 mg, mmol), and dichloromethane (0.5 ml) in this order under nitrogen, and the mixture was stirred at 0 C for 24 h. After a solution of pinacol (177 mg, 1.5 mmol) in N,N-diisopropylethylamine (d = 0.742; 1.3 ml, 7.5 mmol) was added dropwise at 0 C, the mixture was allowed to warm to room temperature and stirred for 1 h. The mixture was dissolved by the addition of dichloromethane (20 ml) and washed with 2M HCl (10 ml). The organic layer was dried over MgSO 4 and evaporated to leave a residue, which was purified by column chromatography on silica gel with hexane/chloroform (1:1) as the eluent to give 2a (102 mg, 69%) Typical procedure for the borylation of other alkenes (entry 10 in Table 2) Ph Ph 2a Bpin In a 10 ml test tube were charged BBr 3 (1.0 M solution in dichloromethane; 2.0 ml, 2.00 mmol), dichloromethane (1.0 ml), 2,6-lutidine (B5) (d = 0.925; 233 µl 2.00 mmol) in this order under nitrogen. The solution was cooled to 0 C, and prop-1-en-2-ylbenzene (1b) (62 mg, mmol) was added dropwise. The mixture was warmed to room temperature and stirred at room temperature for 1 h. After a solution of pinacol (236 mg, 2.0 mmol) in N,N-diisopropylethylamine (d = 0.742; 1.3 ml, 7.5 mmol) was added dropwise at 0 C, the mixture was warmed to room temperature and stirred for 1 h. The mixture was dissolved by the addition of dichloromethane (20 ml) and washed with 2M HCl (10 ml). The organic layer was dried over MgSO 4 and evaporated to leave a residue, which was purified by column chromatography on silica gel with hexane/chloroform (1:1) as the eluent to give 2b (98.5 mg, 77%). A large scale reaction (1.0 mmol) was carried out using prop-1-en-2-ylbenzene (1b) (d = 0.91; 130 µl, 1.00 mmol), BBr 3 (1.0 M solution in dichloromethane; 4.0 ml, 4.00 mmol), dichloromethane (2.0 ml), 2,6-lutidine (B5) (d = 0.925; 464 µl 4.00 mmol), pinacol (480 mg, 4.06 mmol), and N,N-diisopropylethylamine (d = 0.742; 2.6 ml, 14.9 mmol) to give 2b (188 mg, 77%) as an isomeric mixture (E/Z = 86/14) after the chromatographic purification. S7

8 2-(2,2-Diphenylvinyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (2a) 6,7 Purified by column chromatography with hexane/chloroform (1:1) as the eluent to give 2a (102 mg, 69 %). A colorless oil; IR (CHCl 3 ) 2981, 2929, 1607, 1574, 1491, 1446, 1361, 1294, 1215, 1142, 968, 909, 849, 750 cm 1 ; 1 H NMR (400 MH) δ 1.15 (s, 12H), 5.99 (s, 1H), (m, 10 H); 13 C NMR (100 MHz) δ 24.7, 83.3, 127.6, 127.7, , , 129.9, 142.0, 143.2, 159.9; 11 B NMR (128 MHz) δ 30.4 (br); HR-MS (EI-magnetic sector) calcd for C 20 H 23 BO 2 (M) , found ,4,5,5-Tetramethyl-2-(2-phenylprop-1-en-1-yl)-1,3,2-dioxaborolane (2b) 6,8 Ph 2b Purified by column chromatography with hexane/chloroform (1:1) as the eluent to give 2b (98.5 mg, 77%). Obtained as an isomeric mixture (E/Z = 89/11). A colorless oil; IR (CHCl 3 ) 3015, 1982, 1621, 1494, 1448, 1381, 1355, 1324, 1292, 1214, 1143, 979, 850, 750 cm 1 ; 1 H NMR (400 MH) δ for the E isomer 1.31 (s, 12H), 2.41 (d, J = 0.8 Hz, 3H), 5.76 (q, J = 0.8 Hz, 1H), (m, 3H), (m, 2H), for the Z isomer 1.14 (s, 12H), 2.21 (d, J = 1.2 Hz, 3H), 5.47 (q, J = 1.2 Hz, 1H), (m, 5H); 13 C NMR (100 MHz) δ for the E isomer 20.2, 25.0, 83.0, (br), 125.9, 128.0, 128.3, 144.0, for the Z isomer 24.7, 27.8, 83.0, (br), 127.5, , , 143.3, 157.8; 11 B NMR (128 MHz) δ 30.1 (br); HR-MS (EI-magnetic sector) calcd for C 15 H 21 BO 2 (M), , found Bpin 2-(2,2-Di-p-tolylvinyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (2c) 7 Purified by column chromatography with hexane/chloroform (2:1) as the eluent to give 2c (142 mg, 85%). A colorless oil; IR (CHCl 3 ) 2979, 2922, 1599, 1564, 1508, 1410, 1360, 1294, 1142, 968, 849, 824, 754 cm 1 ; 1 H NMR (400 MH) δ 1.16 (s, 12H), 2.32 (s, 3H), 2.37 (s, 3H), 5.90 (s, 1H), (m, 8 H); 13 C NMR (100 MHz) δ 21.2, 21.4, 83.2, 128.1, 128.3, 128.8, 129.9, 137.4, 138.0, 139.1, 140.8, 160.0; 11 B NMR (128 MHz) δ 30.5 (br); HR-MS (EI-magnetic sector) calcd for C 22 H 27 BO 2 (M), , found S8

9 2-(2,2-Bis(4-chlorophenyl)vinyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (2d) Purified by column chromatography with hexane/chloroform (10:1 to 5:1) as the eluent to give 2d (150 mg, 80%). A colorless powder; IR (CHCl 3 ) 2981, 1610, 1490, 1405, 1354, 1293, 1214, 1141, 1091, 1014, 968, 849, 832, 750 cm 1 ; 1 H NMR (400 MH) δ 1.16 (s, 12H), 5.96 (s, 1H), (m, 4H), (m, 4H); 13 C NMR (100 MHz) δ 24.8, 83.5, 128.0, 128.5, 129.3, 131.3, 133.9, 134.4, 139.9, 141.3, 157.6; 11 B NMR (128 MHz) δ HR-MS (EI-magnetic sector) calcd for C 20 H 21 BCl 2 O 2 (M) , found (E)-4,4,5,5-Tetramethyl-2-styryl-1,3,2-dioxaborolane (2f) 9 Purified by column chromatography with hexane/chloroform (1:1) as the eluent to give 2f (71.5 mg, 62 %). A colorless oil; IR (CHCl 3 ) 3017, 1625, 1495, 1450, 1386, 1352, 1323, 1142, 997, 968, 750 cm 1 ; 1 H NMR (400 MH) δ 1.31 (s, 12H), 6.17 (d, J = 18.4 Hz, 1H), (m, 3 H), 7.40 (d, J = 18.4 Hz, 1H) (m, 3 H); 13 C NMR (100 MHz) δ 24.9, 83.5, 127.2, 128.7, 129.0, 137.6, 149.6; 11 B NMR (128 MHz) δ 30.4 (br); HR-MS (EI-magnetic sector) calcd for C 14 H 19 BO 2 (M) , found (E)-4,4,5,5-Tetramethyl-2-(3-phenylprop-1-en-1-yl)-1,3,2-dioxaborolane (2g) 10 This compound is easily undergo protodeboronation under the acidic conditions, therefore the crude product was not treated with 2M HCl after the reaction. Purified by normal silica gel column chromatography withpurified by column chromatography with hexane/chloroform (1:1) as the eluent to give 2g (57.6 mg, 47%). A colorless oil; IR (CHCl 3 ) 3013, 2981, 1636, 1361, 1321, 1215, 1142, 998, 970, 851, 750 cm 1 ; 1 H NMR (400 MH) δ 1.25 (s, 12H), 3.48 (dd, J = 6.2, 1.5 Hz, 2H), 5.45 (dt, J = 18.0, 1.5 Hz, 1H), 6.76 (dt, J = 18.0, 6.2 Hz, 1H), (m, 3H), (m, 2H); 13 C NMR (100 MHz) δ 24.9, 42.4, 83.2, 126.3, 128.6, 129.1, 139.2, 152.6; 11 B NMR (128 MHz) δ 30.1 (br); HR-MS (EI-magnetic sector) calcd for C 15 H 21 BO 2 (M) , found S9

10 (E)-2-(Hex-1-en-1-yl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (2h) 9 This compound is easily undergo protodeboronation under the acidic conditions, therefore the crude product was not treated with 2M HCl after the reaction. Purified by normal silica gel column chromatography with hexane/chloroform (1:1) as the eluent to give 2h (73.9 mg, 70 %). A colorless oil; IR (CHCl 3 ) 2981, 2931, 1638, 1360, 1316, 1215, 1143, 999, 970, 850, 755 cm 1 ; 1 H NMR (400 MHz) δ 0.89 (t, J = 7.2 Hz, 3H), 1.24 (s, 12H), (m, 4H), (m, 2H), 5.40, (dt, J = 18.0, 1.5 Hz, 1H), 6.61 (dt, J = 18.0, 6.4 Hz, 1H); 13 C NMR (100 MHz) 14.0, 22.4, 24.9, 30.5, 35.6, 83.1, 154.9; 11 B NMR (128 MHz) δ 29.8 (br); HR-MS (EI-magnetic sector) calcd for C 12 H 23 BO 2 (M) , found (E)-4,4,5,5-Tetramethyl-2-(oct-1-en-1-yl)-1,3,2-dioxaborolane (2i) 9,11 This compound is easily undergo protodeboronation under the acidic conditions, therefore the crude product was not treated with 2M HCl after the reaction. Purified by normal silica gel column chromatography with hexane/chloroform (1:1) as the eluent to give 2i (52.0 mg, 44%). A colorless oil; IR (CHCl 3 ) 3019, 2980, 2932, 1638, 1363, 1214, 1144, 998, 750 cm 1 ; 1 H NMR (400 MHz) δ 0.88 (t, J = 7.0 Hz, 3H), 1.27 (s, 12H), (m, 6H), (m, 2H), 2.14, (qd, J = 7.0, 1.5 Hz, 1H), 5.42 (dt, J = 18.0, 1.5 Hz, 1H), 6.64 (dt, J = 18.0, 6.4 Hz, 1H); 13 C NMR (100 MHz) 14.2, 22.7, 24.9, 28.3, 29.1, 31.9, 36.0, 83.1, 155.0; 11 B NMR (128 MHz) δ 29.9 (br); HR-MS (EI-magnetic sector) calcd for C 14 H 27 BO 2 (M) , found (E)-2-(6-bromohex-1-en-1-yl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (2j) 12 Purified by column chromatography with hexane/chloroform (1:1) as the eluent to give 2j (56.0 mg, 39%). A colorless oil; IR (CHCl 3 ) 3014, 2980, 2935, 1638, 1362, 1318, 1215, 1143, 969, 849, 752 cm 1 ; 1 H NMR (400 MHz) δ 1.27 (s, 12H), 1.58 (pent, J = 7.5 Hz, 2H), 1.87 (pent, J = 7.2 Hz, 2H), 2.19 (qd, J = 7.6, 1.5 Hz, 2H), 3.38 (t, J = 6.8 Hz, 2H), 5.45 (dt, J = 18.0, 1.5 Hz, 1H), 6.60 (dt, J = 18.0, 6.4 Hz, 1H); 13 C NMR (100 MHz) δ 24.9, 26.8, 32.3, 33.7, 34.9, 83.2, ); 11 B NMR (128 MHz) δ.30.0; HR-MS (EI-magnetic sector) calcd for C 12 H 22 BBrO 2 (M) , found S10

11 (E)-tert-Butyldiphenyl((6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hex-5-en-1-yl)oxy)silane (2k) Purified by column chromatography with hexane/chloroform (1:1) as the eluent to give 2k (160 mg, 26%). A colorless oil; IR (CHCl 3 ) 3016, 2944, 2860, 1637, 1362, 1215, 1143, 1111, 908, 750 cm 1 ; 1 H NMR (400 MHz) δ 1.04 (s, 9H), 1.27 (s, 12H), (m, 2H), 2.14 (qd, J = 7.1, 1.5 Hz, 2H), 3.65 (t, J = 6.0 Hz, 2H), 5.42 (dt, J = 18.0, 1.5 Hz, 1H), 6.63 (dt, J = 18.0, 6.4 Hz, 1H), (m, 6H), (m, 4H); 13 C NMR (100 MHz) δ 19.4, 24.6, 24.9, 27.0, 32.2, 35.7, 63.8, 83.1, 127.7, 130.0, 134.2, 135.7, 154.6; 11 B NMR (128 MHz) δ.30.3; HR-MS (EI-magnetic sector) calcd for C 24 H 32 BO 3 Si (M C 4 H 9 ) , found (2-Ethylbut-1-en-1-yl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (2l) Purified by column chromatography with hexane/chloroform (1:1) as the eluent to give 2l (47.1 mg, 45%). A colorless oil; IR (CHCl 3 ) 2980, 2932, 1635, 1372, 1324, 1215, 1143, 968, 850, 750 cm 1 ; 1 H NMR (400 MHz) δ 1.02 (t, J = 7.4 Hz, 3H), 1.03 (t, J = 7.4 Hz, 3H), 1.26 (s, 12H), 2.14 (qd, J = 7.4, 1.2 Hz, 2H), 2.41 (q, J = 7.4 Hz, 2H), 5.09 (t, J = 1.2 Hz, 1H); 13 C NMR (100 MHz) δ 12.3, 14.5, 25.0, 28.3, 31.3, 82.6, 170.6; 11 B NMR (128 MHz) δ 30.1 (br); HR-MS (EI-magnetic sector) calcd for C 12 H 23 BO 2 (M) , found (S)-4,4,5,5-Tetramethyl-2-(2-(4-methylcyclohex-3-en-1-yl)prop-1-en-1-yl)-1,3,2-dioxaborolane (2n) Purified by column chromatography with hexane/chloroform (1:1) as the eluent to give 2n (75.8 mg, 58%). Obtained as an isomeric mixture (E/Z = 81/19). A colorless oil; IR (CHCl 3 ) 2978, 2922, 1633, 1442, 1372, 1347, 1320, 1261, 1141, 1106, 974, 849, 754 cm 1 ; 1 H NMR (400 MHz) δ for the E isomer 1.27 (s, 12H), 1.99 (d, J = 0.8 Hz), (m, 10H), 5.15 (quint, J = 0.8 Hz, 1H), (m, 1H), for the Z isomer 1.24 (s, 12H), 1.79 (d, J = 1.2 Hz), (m, 9H), (m 1H, Z), 5.11 (q, J = 1.2 Hz, 1H), (m, 1H); 13 C NMR (100 MHz) δ for the E isomer 19.7, 23.6, 24.99, 25.03, 28.0, 30.8, 30.9, 45.1, 82.8, 120.8, 133.8, , for the Z isomer 22.3, 23.8, 24.89, 24.92, 28.6, 30.4, 30.6, 39.5, 82.7, 120.9, 133.7, ; 11 B NMR (128 MHz) δ 30.2 (br); HR-MS (EI-magnetic sector) calcd for C 16 H 27 BO 2 (M) , found S11

12 1-Methyl-3-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-indole (2o) 13,14 This compound is easily undergo protodeboronation under the acidic conditions, therefore the crude product was not treated with 2M HCl after the reaction. Purified by normal silica gel column chromatography with chloroform as the eluent to give 2o (138 mg, 85%). A colorless powder; IR (CHCl 3 ) 3006, 2979, 1533, 1474, 1405, 1296, 1235, 1215, 1143, 1099, 981, 857, 745 cm 1 ; 1 H NMR (400 MHz) δ 1.35 (s, 12H), 3.77 (s, 3H), 7.17 (dt, J = 7.4, 1.2 Hz, 1H), 7.23 (dt, J = 7.4, 1.2 Hz, 1H), 7.30 (d, J = 8.0 Hz, 1 H), 7.51 (s, 1 H), 8.03 (d, J = 7.2 Hz, 1 H); 13 C NMR (100 MHz) δ 25.0, 33.1, 82.8, 109.3, 120.3, 121.9, 122.8, 132.6, 137.9, 138.5; 11 B NMR (128 MHz) δ 30.4 (br); HR-MS (EI-magnetic sector) calcd for C 15 H 20 BNO 2 (M) , found ,4,5,5-Tetramethyl-2-(5-methylthiophen-2-yl)-1,3,2-dioxaborolane (2p) 13 Purified by column chromatography with hexane/chloroform (1:2) as the eluent to give 2b (108 mg, 85%). A colorless oil; IR (CHCl 3 ) 2981, 1538, 1473, 1353, 1325, 1293, 1215, 1142, 1062, 1019, 854, 751 cm 1 ; 1 H NMR (400 MHz) δ 1.33 (s, 12H), 2.53 (d, J = 1.0 Hz, 3H), 6.84 (dq, J = 3.4, 1.0 Hz, 1H), 7.45 (d, J = 3.4 Hz, 1H); 13 C NMR (100 MHz) δ 15.5, 24.9, 84.0, 127.1, 137.8, 147.6; 11 B NMR (128 MHz) δ 28.8 (br); HR-MS (EI-magnetic sector) calcd for C 11 H 17 BO 2 S (M) , found S12

13 5. References (1) Reid, W. B.; Spillane, J. J.; Krause, S. B.; Watson, D. A. J. Am. Chem. Soc. 2016, 138, (2) Wang, T.; Hu, Y.; Zhang, S. Org. Biomol. Chem. 2010, 8, (3) Jabbar, M. A.; Shimakoshi, H.; Hisaeda, Y. Chem. Commun. 2007, (4) Itoh, T.; Matsueda, T.; Shimizu, Y.; Kanai, M. Chem. Eur. J. 2015, 21, (5) Brooks, J. L.; Xu, L.; Wiest, O.; Tan, D. S. J. Org. Chem. 2017, 82, 57. (6) Mkhalid, I. A. I.; Coapes, R. B.; Edes, S. N.; Coventry, D. N.; Souza, F. E. S.; Thomas, R. L.; Hall, J. J.; Bi, S.-W.; Lin, Z.; Marder, T. B. Dalton Trans. 2008, (7) Itami, K.; Tonogaki, K.; Ohashi, Y.; Yoshida, J.-I. Org. Lett. 2004, 6, (8) Wang, C.; Tobrman, T.; Xu, Z.; Negishi, E.-I. Org. Lett. 2009, 11, (9) Shirakawa, K.; Arase, A.; Hoshi, M. Synthesis 2004, (10) Hemelaere, R.; Carreaux, F.; Carboni, B. J. Org. Chem. 2013, 78, (11) Takaya, J.; Kirai, N.; Iwasawa, N. J. Am. Chem. Soc. 2011, 133, (12) Coombs, J. R.; Zhang, L.; Morken, J. P. J. Am. Chem. Soc. 2014, 136, (13) Del Grosso, A.; Singleton, P. J.; Muryn, C. a; Ingleson, M. J. Angew. Chem. Int. Ed. Engl. 2011, 50, (14) Stahl, T.; Müther, K.; Ohki, Y.; Tatsumi, K.; Oestreich, M. J. Am. Chem. Soc. 2013, 135, S13

14 6. 1 H and 13 C NMR Spectral Charts for Compounds Synthesized ,1'-Ethenylidenebis(4-methylbenzene) (1c) 1 H NMR (400 MHz) S14

15 S C NMR (100 MHz)

16 S ,1'-Ethenylidenebis(4-chlorobenzene) (1d) 1 H NMR (400 MHz)

17 S C NMR (100 MHz)

18 S tert-butyl(hex-5-en-1-yloxy)diphenylsilane (1k) 1 H NMR (400 MHz)

19 S C NMR (100 MHz)

20 (2,2-Diphenylvinyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (2a) 1 H NMR (400 MHz) S20

21 S C NMR (100 MHz)

22 11 B NMR (128 MHz) S22

23 S ,4,5,5-Tetramethyl-2-(2-phenylprop-1-en-1-yl)-1,3,2-dioxaborolane (2b) 1 H NMR (400 MHz)

24 S C NMR (100 MHz)

25 11 B NMR (128 MHz) S25

26 (2,2-Di-p-tolylvinyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (2c) 1 H NMR (400 MHz) S26

27 S C NMR (100 MHz)

28 11 B NMR (128 MHz) S28

29 (2,2-Bis(4-chlorophenyl)vinyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (2d) 1 H NMR (400 MHz) S29

30 S C NMR (100 MHz)

31 11 B NMR (128 MHz) S31

32 S (E)-4,4,5,5-Tetramethyl-2-styryl-1,3,2-dioxaborolane (2f) 1 H NMR (400 MHz)

33 S C NMR (100 MHz)

34 11 B NMR (128 MHz) S34

35 (E)-4,4,5,5-Tetramethyl-2-(3-phenylprop-1-en-1-yl)-1,3,2-dioxaborolane (2g) 1 H NMR (400 MHz) O Ph B O 2g S35

36 S C NMR (100 MHz) Ph 2g O B O

37 11 B NMR (128 MHz) Ph O B O 2g S37

38 (E)-2-(Hex-1-en-1-yl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (2h) 1 H NMR (400 MHz) S38

39 S39 13 C NMR (100 MHz)

40 11 B NMR (128 MHz) S40

41 (E)-4,4,5,5-Tetramethyl-2-(oct-1-en-1-yl)-1,3,2-dioxaborolane (1i) 1 H NMR (400 MHz) S41

42 S42 13 C NMR (100 MHz)

43 11 B NMR (128 MHz) S43

44 S (E)-2-(6-Bromohex-1-en-1-yl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (2j) 1 H NMR (400 MHz)

45 S C NMR (100 MHz)

46 11 B NMR (128 MHz) S46

47 S (E)-tert-Butyldiphenyl((6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hex-5-en-1-yl)oxy)silane (2k) 1 H NMR (400 MHz)

48 S C NMR (100 MHz)

49 11 B NMR (128 MHz) S49

50 (2-Ethylbut-1-en-1-yl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (2l) 1 H NMR (400 MHz) S50

51 C NMR (100 MHz) S

52 11 B NMR (128 MHz) S52

53 (S)-4,4,5,5-Tetramethyl-2-(2-(4-methylcyclohex-3-en-1-yl)prop-1-en-1-yl)-1,3,2-dioxaborolane (2n) 1 H NMR (400 MHz) O B O 2n S53

54 S O B O 2n 13 C NMR (100 MHz)

55 11 B NMR (128 MHz) O B O 2n S55

56 Methyl-3-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-indole (1o) 1 H NMR (400 MHz) S56

57 S C NMR (100 MHz)

58 11 B NMR (128 MHz) S58

59 ,4,5,5-Tetramethyl-2-(5-methylthiophen-2-yl)-1,3,2-dioxaborolane (2p) 1 H NMR (400 MHz) S59

60 S C NMR (100 MHz)

61 11 B NMR (128 MHz) S61