A LewisbaseassistedBrønstedbasecatalysis (LBABB) strategy is applied for directasymmetric vinylogous alkylation of allylic sulfones with Morita–Baylis–Hillman (MBH) carbonates, in which a strong Brønstedbase, tert‐butoxy anion, generated in situ from a tertiary amine catalyst and MBH carbonate, is crucial in activating unstabilized nucleophiles. The γ‐regioselective alkylation products were
作者:Yingpeng Su、Yanfen Xu、Junjie Han、Jiyue Zheng、Jing Qi、Tuo Jiang、Xinfu Pan、Xuegong She
DOI:10.1021/jo9000146
日期:2009.4.3
An efficient totalsynthesis of (−)-bitungolideF (6) in 17 steps and 20.1% yield is described herein. Key steps involve a Myers asymmetric alkylation to introduce the C6 methyl with proper stereochemistry, a Claisen-like cyclization to construct the α,β-unsaturated δ-lactone and a Julia−Kocienski olefination to assemble the conjugated diene moiety.