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. (C) 2000 Published by Elsevier Science Ltd.