反应详情

To a solution of 32 (4.68 g, 13.1 mmol) in THF (100 mL) at −78° C. was added dropwise over 10 min n-butyllithium (1.6 M in hexanes, 18.4 mmol). After 3 h of stirring under argon, 1-bromo-2-methylpropane (2.14 mL, 19.7 mmol) was added dropwise over 5 min, and the mixture was stirred for 2 h at −78° C. and overnight at rt. The reaction mixture was quenched with water (10 mL) and the excess organic solvent was removed under reduced pressure. The crude mixture was extracted with three 100-mL portions of EtOAc. The combined organic extracts were washed with saturated aqueous NaCl, dried over Na2SO4, and concentrated. Flash chromatography over silica gel (1/9 EtOAc:hexane) gave pure 26 as a colorless solid (5.0 g, 92%): Rf=0.75 (1/9 EtOAc:hexane); mp 67–69° C.; 1H NMR (300 MHz, CDCl3) δ 7.83 (d, J=6.0 Hz, 4H), 7.41 (m, 6H), 5.88 (m, 1H), 4.97 (dd, J=17.1, 1.7 Hz, 1H), 4.88 (dd, J=10.1, 1.7 Hz, 1H), 3.04 (m, 2H), 2.49 (t. J=4.3 Hz 1H), 2.44 (t, J=4.1 Hz, 1H), 2.08 (d, J=5.1 Hz, 2H), 1.98 (m, 4H), 1.79 (m, 1H), 1.54 (m, 2H), 0.82 (d, J=6.7 Hz, 6H); 13C NMR (75 MHz, CDCl3) δ 141.5, 136.7, 132.9, 129.9, 127.7, 113.0, 45.7, 39.9, 28.3, 27.2, 24.6, 24.3, 24.2, 11.0; IR (film) 3068 (m), 3043 (m), 2951 (s), 2912 (s), 2863 (m), 1432 (s), 1274 (w), 1113 (s), 997 (m), 913 (m), 738 (s), 705 (s) cm−1; MS (EI) m/e (rel. intensity) 289 (M+-123, 3), 237 (8), 183 (72), 175 (100), 159 (32), 143 (17), 119 (16), 105 (35); HRMS (FAB) calcd for C24H32S2Si: 412.1715 (MH+-1), found: 412.1727. Anal. Calcd for C24H32S2Si: C, 69.84; H, 7.82. Found: C, 70.08; H, 8.07.

1. stirringthe mixture was stirred for 2 h at −78° C. and overnight at rt
2. customThe reaction mixture was quenched with water (10 mL)
3. customthe excess organic solvent was removed under reduced pressure
4. extractionThe crude mixture was extracted with three 100-mL portions of EtOAc
5. washThe combined organic extracts were washed with saturated aqueous NaCl
6. dry with materialdried over Na2SO4
7. concentrationconcentrated