Reactions of β-benzylthio- and β-benzylsulphonyl-cinnamic acids and esters

Abstract

Configurations have been assigned to the title compounds from their n.m.r. spectra. Cyclisation of cis- and trans-β-(benzylthio)cinnamic acids gave the corresponding 3-benzylthioinden-1-ones; Dieckmann reactions with ethyl β-(benzylsulphonyl)cinnamates afforded the corresponding 2,5-diphenylthiophen-3(2H)-one 1,1-dioxides. Ethyl α-ethoxymethyl-trans-cinnamate is readily obtained from ethyl β-benzylsulphonyl-α-methyl-cis-cinnamate.