Effect of Rhodium Carbenoid Structure on Cyclopropanation Chemoselectivity

Rhodium-stabilized carbenoids derived from aryldiazoacetates and vinyldiazoacetates undergo highly chemoselective intermolecular cyclopropanations, and this selectivity has been quantified by a Hammett study. These donor/acceptor substituted carbenoids are much more chemoselective than the traditional carbenoids derived from alkyl diazoacetates.