Efficient Syntheses of Highly Substituted Organic Molecules Starting from Torquoselective Olefination

本文发展了炔醇酯与羰基化合物的高立体选择性烯化反应，并通过理论计算和一般性分析阐明了反应机理。炔基酮通过炔酸酯的烯化反应得到了具有高E-选择性的烯炔化合物，其中炔基作为给电子基团参与了烯炔选择性反应。烯烃转化为β-烷氧基二乙烯基酮，再经催化Nazarov反应得到α-烷氧基环戊烯酮，产率较高。将此环合反应应用于百部生物碱的合成研究。

We have developed the highly stereoselective olefination of carbonyl compounds with ynolates, and clarified the reaction mechanism by the theoretical calculations and the generality. The olefination of alkynyl ketones via ynolates provided the corresponding en-yne compounds with high E-selectivity, in which the alkynyl group works as an electron donating group in the torquoselectivity. The resulting olefins were converted into β-alkoxy divinyl ketones, which was subjected to the catalytic Nazarov reaction to afford α-alkoxy cyclopentenones in good yield. This cyclization was applied to the synthetic study of stemona alkaloids.