Synthesis of glyoxylyl peptides using a phosphine labile α,α′-diaminoacetic acid derivative

We describe in this letter the preparation of a novel protected alpha,alpha'-diaminoacetic acid derivative that acts as a masked glyoxylic acid equivalent. The reagent could easily be introduced on a peptide chain using standard Fmoc/tert-butyl solid-phase methods and resisted to the TFA treatment allowing the deprotection and cleavage of the peptide. Unmasking of the glyoxylyl group was performed in solution in the presence of a phosphine. (C) 2004 Elsevier Ltd. All rights reserved.