The bifunctional catalyst 2-hydroxypyridine (2-pyridone) is shown to promote the intramolecular aminolysis of the polyfunctionalized long-chain amino trichloroethyl ester 8 to afford cryptophycin-51 (4). This process for the construction of the macrocyclic core of cryptophycin derivatives is noteworthy for its convenience, avoidance of expensive coupling reagents, and use of mild reaction conditions. © 1998 Elsevier Science Ltd. All rights reserved.