Dimerization of 3,4-disubstituted cinnamic acids and esters

Abstract

Cinnamic (3-phenylpropenoic) acids and esters bearing hydroxy and/or alkoxy groups at C-3 and C-4 on the benzene ring, 1 undergo cyclodimerization on treatment with trifluoroacetic acid to yield the corresponding [t-3-aryl-c-2-carboxy[or alkoxycarbonyl]-r-1-indanyl]acetic acids or esters 2.