acetonitrile, yielding predominantly the kinetic cis-configured adduct as a racemate. Thermodynamically more stable trans-configuration could be attained either via heating the cis-configured product in DMSO or via the action of a base (imidazole) in the course of CDI-promoted esterification or amidation of the carboxylic acid function in the initial adducts. Further manipulation of the remaining N-acylhydrazone