Some Friedel-Crafts reactions of γ-butyrolactone

Abstract

Benzene reacts with γ-butyrolactone and aluminium chloride to give tetralone, but no detectable amount of 3-methylindan-1-one. p-Dichlorobenzene, p-difluorobenzene and m-dichlorobenzene give exclusively the indanones in good yield. Chlorobenzene gives a mixture of tetralones and indanones in ratio 78 : 22 and the major product of each type arises from alkylation ortho to chlorine. γ-Butyrolactone is isomerized to crotonic acid by treatment with excess aluminium chloride at 150° and the indanones probably arise by this route.