Synthesis of polyhydroxysterols (I): Synthesis of 24-methylenecholest-4-en-3β,6β-diol, a cytotoxic natural hydroxylated sterol

Article abstract of DOI:10.1016/S0039-128X(00)00132-X

Starting from stigmasterol (2), 24-methylenecholest-4-en-3β,6β-diol (1), a cytotoxic natural dihydroxylated sterol, was synthesized via 10 steps in 20% overall yield. The introduction of a side-chain of sterol was achieved by solid-liquid phase-transfer Wittig reaction using (3-methyl-2-oxo)butyltriphenylarsonium bromide (12) and K₂CO₃. Construction of the steroidal nucleus was finished by the addition of 3β-acetoxycholest-5,6-en-24-one (7) with NBA in dioxane under ambient temperature and by the elimination of 3β, 6β-diacetoxy-5a-bromocholestane-24-one (9). The spectral data of the synthetic product (1) are completely consistent with those of the natural compound (1). Copyright (C) 2001 Elsevier Science Inc.