A general and highly convenient method for the synthesis of N-protected alpha-aminophosphinic acids, suitable for side chain elongation either from N-, P-, or C- termini to form a variety of phosphinic peptides, has been developed. The desired phosphinic acids were obtained in moderate to satisfactory yield by a three-component condensation reaction of benzyl carbamate, an aldehyde, and an alkylphosphonous acid (or its 1-adamantanamine salt) in acetyl chloride under very mild conditions. Copyright (C) 1996 Elsevier Science Ltd.