[C:1]1([S:7]([C:10]2[C@H](O)C[C@H](C)[CH2:14][CH:15]=2)(=O)=O)[CH:6]=[CH:5][CH:4]=[CH:3][CH:2]=1.[CH3:18]CN(CC)CC.CS(Cl)(=O)=O.[Li+].C[Si]([N-][Si](C)(C)C)(C)C.[CH2:40]1[CH2:44][O:43][CH2:42][CH2:41]1>CC(O)C.C1C=CC=CC=1>[CH3:18][C@H:40]1[CH:41]=[CH:42][C:10]([S:7][C:1]2[CH:6]=[CH:5][CH:4]=[CH:3][CH:2]=2)=[CH:15][CH2:14][C@H:44]1[OH:43](4S)-4-Methyl-cyclohexa-1,5-dienesulfonyl)-benzene (29z). To a solution of 24z (355 mg, 1.40 mmol) and Et3N (0.19 mL, 1.40 mmol) in THF (10 mL) at 0° C. was added 0.11 mL (1.40 m-mol) of MsCl dropwise. After stirring at 0° C. for 1 h, the reaction mixture was cooled to −78° C., and freshly prepared LiHMDS (2.8 mL, 1.0 M in THF, 2.8 mmol) was added dropwise over 20 min. After stirring at −78° C. for 15 min, the reaction was quenched with saturated aqueous NH4Cl, diluted with ether, separated, further extracted with ether. The organic layers were washed with brine, dried over Na2SO4, and concentrated via rotary evaporation. The crude residue was purified with flash column chromatography (ethyl acetate/hexanes; 1:3) to provide 303 mg (92% yield) of 29 as a white solid with 99% ee by HPLC (Chiralpak AD 1.0 ml/min; 95:5 Hex:2-propanol, 19.57 min for minor enantiomer, 20.51 min for major enantiomer). Mp 54.0-56.0° C.; 1H NMR (CDCl3, 300 MHz): δ 7.85 (m, 2H), 7.48-7.61 (m, 3H), 6.91 (t, J=4.2 Hz, 1H), 6.01 (d, J=10.3 Hz, 1H), 5.81 (dd, J=10.3, 3.9 Hz, 1H), 2.38-2.57 (m, 2H), 2.15 (ddd, J=17.1, 11.1, 4.5 Hz, 1H), 0.98 (d, J=6.6 Hz, 3H); 13C NMR (CDCl3, 75 MHz): δ139.9, 138.2, 136.4, 134.5, 133.2, 129.1, 127.6, 117.4, 30.6, 26.9, 19.4. MS(EI) m/z 233 [M−H]+; HRMS (EI) calcd for C13H13O2S, 233.0636; found, 233.0632.
Loading…
