Asymmetric Synthesis of α-Alkyl-α-amino Acids from Chromium-Carbene-Complex-Derived β-Lactams

Article abstract of DOI:10.1021/jo00074a016

Optically active bicyclic β-lactam 3 was synthesized by photolysis of optically active oxazolidine carbene chromium complex 1 with oxazine 2.Conversion of the oxazolidine to the oxazolidinone gave a bicyclic β-lactam readily α-alkylated.Cleavage of the alkylated β-lactam gave optically active ester aldehyde 7, which was converted to a number of optically active α-alkyl-α-amino acids.These include (R)-α-methylserine, (S)-α-methylglutamic acid, (S)-α-methylornithine, (S)-vinylalanine, (S)-ethynylalanine, and (S)-2-methyl-2,3-diaminopropionic acid.