Efficient Synthesis of 1-Azadienes Derived from alpha-Aminoesters.Regioselective Preparation of alpha-Dehydroamino Acids,Vinylglycines,and alpha-Amino Acids

摘要

An efficient synthesis of 1-azadienes derived from alpha-aminoesters is achieved through an aza-Wittig reaction of phosphazenes with beta,gamma-unsaturated alpha-ketoesters.Regioselective 1,2-reduction of these functionalized 1-azadienes affords vinylglycine derivatives,while conjugative 1,4-reduction gives alpha-dehydroamino acid compounds.Reduction of both the carbon-carbon and the imine-carbon-nitrogen double bonds leads to the formation of alpha-amino acid derivatives.