Cobalt-Catalyzed Intramolecular Hydroacylation Involving Cyclopropane Cleavage

Abstract

A simple cobalt-diphosphine catalyst has been found to efficiently promote intramolecular cyclization of ortho-cyclopropylvinyl- and cyclopropylidenemethyl-substituted benzaldehydes into benzocyclooctadienone and benzocycloheptadienone derivatives, respectively. This ring-opening hydroacylation likely involves aldehyde C-H oxidative addition, olefin insertion, cyclopropane cleavage by β-carbon elimination, and C-C bond-forming reductive elimination, as was supported by mechanistic experiments and DFT calculations.

Keywords: C−C bond cleavage; C−H activation; cobalt; cyclopropanes; hydroacylation.