THE SOLID-PHASE SYNTHESIS OF ALPHA,ALPHA-DISUBSTITUTED UNNATURAL AMINO-ACIDS AND PEPTIDES (DI-UPS)

This paper reports a new, mild procedure (''di-UPS'') for the solid ph ase synthesis of racemic alpha,alpha-disubstituted amino acids (1) and epimeric alpha,alpha-disubstituted terminal amino acid residues (2, R -3=H) in a resin bound peptide. The synthetic route is compatible with most protected amino acid side chains and can be used in a continuing solid phase synthesis. DI-UPS should find wide applicability in the d esign and solid phase synthesis of hybrid amino acids and peptides, an d the construction of basis units for combinatorial chemistry. (C) 199 7 Elsevier Science Ltd.