Interrupted Polonovski Strategy for the Synthesis of Functionalized Amino Acids and Peptides

The alpha-functionalization of carbamate-protected hydroxylamine glycine derivatives, acting as imine surrogates via an interrupted Polonovski reaction, is described to access functionalized amino acid derivatives. The addition of C, N, O, and S nucleophiles was achieved in a one-pot procedure in 37% to 92% yield. This method could be extended to dipeptide derivatives for the functionalization of both the C-terminus and N-terminus.