Extracyclic stereocontrolled alkylation of (1R,5S)-4-ethyl-6,6-dimethyl-3-(phenylsulfonyl)bicyclo[3.1.1]hept-3-en-2-one. A highly stereocontrolled synthesis of (-)-kanshone A
Regio- and diastereoselective alkylation of (1,5-4-ethyl-6,6-dimethyl-3-(phenylsulfonyl)bicyclo[3.1.1]hept-3-en-2-one
作者:Michiharu Kato、Masataka Watanabe、Bahlul Z. Awen、Bernhart Vogler
DOI:10.1016/0040-4039(91)80128-s
日期:1991.12
Alkylation of (1,5)-4-ethyl-6,6-dimethyl-3-(phenylsulfonyl)-bicyclo[3.1.1]hept-3-en-2-one (3) with allyl bromide proceeded at the γ position to the conjugated enone system in regio- and diastereoselective fashion, providing (1,5-4-((1)-1-methyl-3-butenyl)-6,6-dimethyl-3-(phenylsulfonyl)bicyclo[3.1.1]hept-3-en-2-one (9a) in good yield. An analogous trend was observed in alkylation of 3 with other representative