Chiral ruthenium porphyrin-catalyzed asymmetric cyclopropanation of 1,3-dienes with tert-butyl 2-cyano-2-diazoacetate as the carbene source

Abstract

The chiral ruthenium porphyrin complex (S,R)-cmcpor-RuCO effectively catalyzes the asymmetric cyclopropanation reaction of 1,3-diene derivatives and tert-butyl 2-cyano-2-diazoacetate to produce highly enantio-enriched substituted vinylcyclopropanes under mild reaction conditions. This catalytic reaction can be applied to a variety of substrates, including alkyl- and aryl-substituted 1,3-diene derivatives (22 examples), as well as diene derivatives from natural products (8 examples). High product yields (up to 97%) and high enantioselectivities (up to 95% ee) were achieved. Monitoring the generation and transformation of ruthenium carbene intermediates using 1H NMR spectroscopy provides insights into the catalytic reaction mechanisms.