SYNTHESIS AND VALENCE ISOMERIZATION OF 7-ALKYL-7-METHOXYCARBONYLCYCLOHEPTATRIENES

Abstract

Abstract 7-Methyl- (IV), 7-ethyl- (V) and 7-isopropyl-7-methoxycarbonylcycloheptatrienes (VI) could be easily synthesized by alkylation of cycloheptatriene-7-carboxylic acid (I), followed by methylation with diazomethane. Valence isomerization between cycloheptatriene (a-form) and norcaradiene (b-form) is observed and steric factors controlling the equilibrium are discussed.