反应详情

Following the general procedure for the reductive ring opening of benzylidene-type acetals of 1,3-diols of Description 9, 9.5 g (43.5 mmol) of (4S)-5,5-dimethyl-2-phenyl-4-vinyl-1,3-dioxane (7c) was reacted with 25.0 mL (19.9 g, 140.0 mmol) of diisobutylaluminum hydride [(iBu)2AlH, DIBAL(H)] in 150 mL of anhydrous dichloromethane (DCM). After acidic aqueous work-up, the crude material was purified by silica gel column using mixtures of methyl tert-butyl ether (MTBE) and hexane (Hxn) as eluent (MTBE/Hxn=1:9→MTBE/Hxn=1:6→MTBE/Hxn=1:3) to provide 8.4 g (88% yield) of the title compound (7) as a colorless liquid. Rf=0.45 (Et2O/Hxn=1:1). 1H NMR (400 MHz, CHCl3): δ=0.91 (s, 3H), 0.92 (s, 3H), 2.82 (t, J=5.9 Hz, 1H), 3.38 (dd, J=10.8, 6.0 Hz, 1H), 3.55 (dd, J=10.8, 6.0 Hz, 1H), 3.64 (d, J=8.0 Hz, 1H), 4.31 (d, J=12.0 Hz, 1H), 4.62 (d, J=11.6 Hz, 1H), 5.22-5.28 (m, 1H), 5.36-5.40 (m, 1H), 5.81 (ddd, J=17.2, 10.4, 8.4 Hz, 1H), 7.27-7.38 (m, 5H) ppm. MS (ESI) m/z: 221.1 (M+H)+, 243.1 (M+Na)+. The analytical data for the compound was consistent with the proposed structure and the data given in the literature (Ito et al., Synthesis 1993, 137-140; and Mandel et al., Org. Lett. 2004, 6(26), 4801-4803).

1. customAfter acidic aqueous work-up, the crude material was purified by silica gel column