Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853-1301, United States.
J Am Chem Soc. 2020 Apr 29;142(17):8029-8035. doi: 10.1021/jacs.0c02653. Epub 2020 Apr 20.
Reactions facilitating inversion of alkene stereochemistry are rare, sought-after transformations in the field of modern organic synthesis. Although a number of isomerization reactions exist, most methods require specific, highly activated substrates to achieve appreciable conversion without side product formation. Motivated by stereoinvertive epoxide carbonylation reactions, we developed a two-step epoxidation/deoxygenation process that results in overall inversion of alkene stereochemistry. Unlike most deoxygenation systems, carbon monoxide was used as the terminal reductant, preventing difficult postreaction separations, given the gaseous nature of the resulting carbon dioxide byproduct. Various alkyl-substituted - and -epoxides can be reduced to - and -alkenes, respectively, in >99:1 stereospecificity and up to 95% yield, providing an alternative to traditional, direct isomerization approaches.
促进烯烃立体化学反转的反应在现代有机合成领域是罕见的、备受追捧的转化。尽管存在许多异构化反应，但大多数方法需要特定的、高度活化的底物才能在不形成副产物的情况下实现可观的转化率。受立体反转环氧化合物羰基化反应的启发，我们开发了一种两步环氧化/脱氧过程，导致烯烃立体化学的整体反转。与大多数脱氧系统不同，一氧化碳被用作末端还原剂，由于生成的二氧化碳副产物为气态，避免了困难的反应后分离。各种烷基取代的 - 和 - 环氧化物可以分别还原为 - 和 - 烯烃，立体选择性 >99:1，产率高达 95%，为传统的直接异构化方法提供了替代方案。
