Efficient Syntheses of Highly Substituted Organic Molecules Starting from Torquoselective Olefination

研究了羰基化合物与醇酯的高立体选择性烯烃反应，并通过理论计算和通用性阐明了反应机理。炔基酮经烯醇酯的烯化反应得到了具有高e选择性的炔基化合物，其中炔基作为给电子基团具有选择性。将烯烃转化为β-烷氧基二乙烯基酮，通过纳扎罗夫催化反应得到收率较高的α-烷氧基环戊烯酮。该环化方法已应用于牡丹生物碱的合成研究。

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.