Thermal and photodimerization of Benzo[b]thiophen-3-carboxylic acid 1,1-Dioxide

Abstract

Benzo[b]thiophen-3-carboxylic acid 1,1-dioxide is shown to undergo dimerization to a cyclobutane under the influence both of ultraviolet light and of heat, whereas the corresponding methyl ester is dimerized only by ultraviolet light. The dimer is shown to be of the 'head-to- head' type, with trans stereochemistry about the cyclobutane ring.