Selective synthesis of phenylpropanoid carbonyl and diphenylalkyl derivatives via para-alkylation of tertiary anilines with cyclopropanol.

A facile method for the para-selective C-H alkylation of tertiary anilines with cyclopropanol has been developed. By simply tuning the reaction parameters, two distinct product classes, namely phenylpropanoid carbonyls and diphenylalkyl derivatives, can be selectively accessed. The palladium-catalysed system delivers carbonyl products in high yields, whereas catalyst-free conditions favour the formation of diphenylalkyl compounds. This synthetic protocol features a broad substrate scope and good functional group compatibility. Mechanistic investigations demonstrate that both transformations proceed through electrophilic aromatic substitution following two divergent reaction pathways.