Asymmetric Synthesis of Aminocyclopropanes and N-Cyclopropylamino Alcohols Through Direct Amidocyclopropanation of Alkenes Using Chiral Organozinc Carbenoids



Chiral N-(diethoxymethyl)oxazolidinones, prepared from the corresponding oxazolidinones by heating in triethyl orthoformate, can be used as organozinc carbenoid precursors for the direct enantioselective amidocyclopropanation of alkenes. The reaction is successful with a wide range of oxazolidinones and alkenes and proceeds with moderate to excellent yield and stereoselectivity. In most cases the trans/exo amidocyclopropane product is favoured, although certain cyclicalkenes such as indene favour the formation of the endo cyclopropane. The products can be readily elaborated to produce cyclopropylamino alcohols and amino acids.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)