Catalytic Cyclopropanation of Alkenes with Ethyl Nitrodiazoacetate. A Facile Synthesis of Ethyl 1-Nitrocyclopropanecarboxylates

Article abstract of DOI:10.1021/jo00274a027

Ethyl 1-nitrocyclopropanecarboxylates are formed in the reaction between alkenes and ethyl nitrodiazoacetate using a catalytic amount of rhodium(II) acetate.Ethyl oxoacetates are obtained as side products.These result from an ene reaction between the alkene and an intermediate acyl nitroso compound.Relative reactivities and stereoselectivities for catalytic rhodium(II) acetate reactions of ethyl nitrodiazoacetate with 12 alkenes to yield cyclopropanes and ene products are reported.Electron-rich, sterically undemanding alkenes are the most reactive and give the best yields of cyclopropanes.Less reactive, crowded alkenes give poor yields of cyclopropanes and enhanced yields of ene products.A comparison with the relevant data for ethyl diazoacetate reveals that the reaction with ethyl nitrodiazoacetate is more sensitive to the electronic and steric nature of the reactant alkene.Doyle's model for catalytic cyclopropanation with rhodium(II) acetate is invoked to explain these data.