A divergent construction of fused and bridged carbo-/heterocyclic scaffolds via cascade reactions of aryl azomethine imines with vinyl cyclic carbonates

Abstract

Presented herein is a divergent synthesis of indene-fused pyrazoles and bridged benzodiazepines tethered with a versatile reactive hydroxymethyl group via the cascade reactions of aryl azomethine imines with vinyl cyclic carbonates. Mechanistically, the reactions are initiated by TM-catalysed aryl C(sp²)–H bond activation/cyclometallation, followed by vinyl coordination/migratory insertion, elimination/decarboxylation and intramolecular [3 + 2] cycloaddition. By using this developed protocol, a number of fused and bridged carbo-/heterocyclic products with pharmaceutical and agrochemical significance are readily obtained from easily obtainable substrates in an efficient and atom-economical manner. Moreover, the usefulness of this method is showcased by gram-scale preparations and diverse transformation of the products.