Stereospecific Methanol Elimination and Hidden Hydrogen Transfer in Cyclic Diesters under Electron Impact

Abstract

Abstract Elimination of CH 3 OH under electron impact occurs in trans ‐1,2‐ and 1,3‐dicarbomethoxycycloalkanes to a greater extent than in the cis ‐isomers. In the trans ‐diesters, one of the α‐hydrogen atoms is abstracted in the course of the elimination. In the methyl esters of cyclohexane 1,4‐dicarboxylic acids, the elimination of CH 3 OH is also specific to the trans ‐isomer, but the abstracted hydrogen atom does not originate at the α‐position. This result is explained by a stereospecific hidden hydrogen migration step, preceding the elimination.