Extension of the previously reported modification of Passerini multicomponent reaction (involving condensation with N-Boc-alpha-aminoaldehydes followed by a deprotection-transacylation step) to alpha-aminoacid derived carboxylic or isocyanide components, allowed the highly convergent and short synthesis of complex peptidomimetic structures, including known potent inhibitors of serine proteases. (C) 2002 Elsevier Science Ltd. All rights reserved.