Synthesis of 2-substituted bicyclo[2.1.0]pentanes from bicyclo[3.1.0]hexan-2-one

Abstract

Bicyclo[3.1.0]hexan-2-one (1) was converted into the 3-diazo derivative (4), which was ring-contracted thermally to give a variety of amides and esters of bicyclo[2.1.0] pentane-2-carboxylic acid as exo- and endo-stereoisomers. Conversion of the acids into the corresponding methyl ketones and then Baeyer–Villiger reaction has led to endo- and exo-bicyclo[2.1.0] pentan-2-yl acetates which differed markedly in solvolytic reactivity.