Alternative and Chemoselective Deprotection of the α‐Amino and Carboxy Functions of N‐Fmoc‐Amino Acid and N‐Fmoc‐Dipeptide Methyl Esters by Modulation of the Molar Ratio in the AlCl3/N,N‐Dimethylaniline Reagent System

Abstract The amino and carboxy functions in N ‐Fmoc‐α‐amino acid and N ‐Fmoc‐peptide methyl esters can be alternatively and chemoselectively deprotected by treatment with the reagent system AlCl 3 / N , N ‐dimethylaniline (DMA). The chemoselectivity of the process is controlled by modulating the relative molar ratio of the Lewis acid and DMA. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)