Irreversible Oxy-2-azonia-Cope Rearrangements for the Synthesis of Functionalized Allyl [alpha]-Amino Acid Derivatives

A general method to synthesize functionalized allyl [alpha]-amino acid derivatives through an irreversible oxy-2-azonia-Cope rearrangement is reported. In the presence of AlCl3, the reaction of imino ethyl glyoxalates with various [beta],[gamma]-unsaturated ketones furnished the corresponding allyl [alpha]-amino acid derivatives. The key to the success of this method is the amide bond formation, which makes the rearrangement irreversible. This reaction system constitutes a new strategy for the synthesis of unusual allyl glycine derivatives, which are valuable synthetic intermediates. An efficient and operationally simple three-component version of this reaction was also performed.