School of Chemistry, Monash University , Clayton 3800, Victoria, Australia.
J Am Chem Soc. 2014 Oct 15;136(41):14397-400. doi: 10.1021/ja508542n. Epub 2014 Oct 2.
The enantioselective vinylogous Michael/aldol cascade is an underdeveloped approach to cyclohexenes. Herein we describe a highly enantioselective (most ≥ 98:2 er) and diastereoselective (all ≥ 15:1 dr) N-heterocyclic carbene catalyzed cycloisomerization of acyclic dienyl esters to cyclohexyl β-lactones. Derivatizations avail cyclohexenes bearing four contiguous stereogenic centers, while mechanistic studies support olefin isomerization prior to cyclization.
对映选择性乙烯基迈克尔/Aldol 级联反应是一种尚未充分开发的环己烯合成方法。在此,我们描述了一种高对映选择性(大多数 ≥ 98:2 er)和非对映选择性(所有 ≥ 15:1 dr)的 N-杂环卡宾催化的非环二烯基酯的环异构化反应,生成环己基 β-内酰胺。衍生化反应可得到带有四个连续立体中心的环己烯,而机理研究支持在环化之前进行烯烃异构化。