Stereochemical Study on 1,3-Dipolar Cycloaddition Reactions of Heteroaromatic N-Ylides with Symmetrically Substituted cis and trans Olefins

• DOI: 10.1246/bcsj.58.3137
• Publication Date: 2006-07-26T01:27:24Z
• Authors: Otohiko Tsuge; Shuji Kanemasa; Shigeori Takenaka
• Keywords: Stereospecificity; Cis–trans isomerism

Abstract Stereochemistry of the cycloadditions twenty-four heteroaromatic N-ylides with several symmetrically substituted cis and trans olefins has been investigated. Cyclic acyclic cycloadd to form ylides in a highly endo-selective manner giving almost quantitative yields stereospecific endo 3+2 cycloadducts. N-Ylides stabilized substituent carbonyl type react mostly two stereoisomeric cycloadducts anti ylides. In most cases, they undergo interconversion through retro cycloaddition process, isomer ratios easiness transformation depending upon nature size substituents on five-membered ring which built up step. On other hand, noncarbonyl give stereoselective as single isomers are assigned syn