Reaction Steps
(S)-Pinanediol (1S)- (1-chloroethyl)boronate (18) was prepared by the published method [Matteson, D. S. et al., J Am. Chem. Soc., 1986, 108:812-819]. Reaction of 18 with bromo(1-ethylethenyl)magnesium (8a) was carried out in a similar manner to that described above for the reaction of 7 with 8a to make 9a. The (S)-pinanediol [2-ethyl-(1-buten-3-yl)]boronate (19a) obtained after running the reaction mixture through a short silica column to remove inorganic salts and concentration contained 5% pinanediol (1-ethylethenyl)boronate as a contaminant according to NMR analysis; data for 19a: 1H NMR (CDCl3) δ0.83 (s, 6) 1.04 (t, 5), 1.15 (d, 3), 1.2 (s, 6), 1.36 (s, 3), 1.4 (d, 2) 1.7-2.4 (m) 4.2 (dd, 1), 4.7 (m, 1), 4.75 (q, 1); 13C NMR (CDCl3): δ12.4, 14.8, 24.0, 26.3, 27.0, 28.4, 29.5, 35.6, 39.4, 51.2, 77.7, 85.5, 127.7, 154.1; HRMS: calcd for C16H27BO2 (M+) 262.2104; found, 262.2111. Conversion of 19a to (S)-pinanediol [2-ethyl-3-methyl-(1-buten-4-yl)]boronate (20a) was done under conditions similar to those used to convert 9a to 10a; data for 20a: 1H-NMR (CDCl3): δ0.85 (s, 3) 1.03 (t, 3), 1.08 (d, 3), 1.42 (s, 3), 1.56 (d, 3) 1.7-2.4 (m, 3), 3.6 (q, 1), 4.25 (dd, 1), 4.65 (q, 1), 4.8 (m, 1), 13C NMR (CDCl3, RT): d 12.44,19.33, 22.73, 24.00, 26.51, 28.69, 32.13, 35.26, 35.95, 39.49, 51.18, 69.79, 78.08, 105.38, 158.01. HRMS: calcd for C17H29BO2 (M+) 276.2261; found, 276.2265. Conversion of 20a to (S)-pinanediol [2-ethyl-3-methyl-(1-hexen-5-yl)]boronate (21a) was done in a manner similar to the conversion of 10a to 12a, data for crude intermediate (S)-pinanediol [2-ethyl-5-chloro-3-methyl-(1 -penten-5-yl)]boronate (not illustrated): 1H-NMR (CDCl3, RT): δ0.8-2.5 (m), 2.6 (m, 1), 3.42 (dd, 1), 4.30 (dd, 1), 4.6 (m, 2), 13C NMR (CDCl3) δ12.3, 19.01, 20.6, 23.94, 26.4, 26.98, 28.43, 35.23, 37.47, 37.81, 39.38, 40.01, 51.46, 78.41, 86.59, 108.15, 153.87; HRMS: calculated for C18H30BO2CI (M+) 324.2027, found 324.2019; data for 21a: 1H-NMR (CDCl3): δ0.8-2.5 (m), 1.78 (m, 2), 2.6 (m, 1), 3.44 (dd, 2), 4.3 (dd, 1), 4.6 (m, 1), 4.7 (m, 1); 13C NMR (CDCl3) δ12.3, 16.01, 20.1, 23.96, 25.6, 26.39, 27.06, 28.6, 35.42, 35.6, 38.1, 39.3, 39.4, 51.22, 77.58, 85.14, 106.45, 156.35; HRMS calcd for Cl9H33BO2 (M+) 304.2574; found, 304.2550. Conversion of 21a to (S)-pinanediol [2-ethyl-3,5- dimethyl-(1-octen-6-yl)]boronate (22a) was carried out in a similar manner to that described for 12a to 14a, data for intermediate (S)-pinanediol [2-ethyl-6-chloro-3, 5-dimethyl-(1-hexen-6-yl)]boronate: 1H-NMR (CDCl3): d 0.8-2.5 (m) 2.6 (m, 1), 3.42 (d, 1), 4.30 (dd, 1), 4.6 (m, 2); 13C NMR (CDCl3) δ153.87, 108.15, 86.59, 78.4151.46, 40.01, 39.38, 37.81, 37.47, 35.23, 28.43, 26.98, 26.40, 23.94, 20.6, 12.3; data for 22a: 13C NMR (CDCl3) δ156.13, 106.38, 85.26, 78.43, 77.56, 67.8, 51.1, 51.0, 39.46, 38.1, 37.5, 34.1, 28.6, 27.1, 26.5, 25.9, 23.9, 19.85, 17.1, 12.4, 7.8. Conversion of 22a to 15a was carried out with hydrogen peroxide in the same manner as the conversion of 14a to 15a.
