A mechanistic study on the catalytic, asymmetric α-bromination of acid chlorides

The mechanism of the catalytic, asymmetric alpha-bromination of acid chlorides is probed through a series of crossover experiments, ion-pairing tests, and kinetic resolution studies to shed light on the factors that contribute to, and limit the production of, optically-active alpha-bromo esters. In order to understand better the observed sense of induction, as well as the high degree of enantiomeric excess exhibited by these products, extensive molecular modeling is employed on the relevant transition states. Finally, the usefulness of the alpha-bromo ester products is demonstrated by their simple derivatization into chiral epoxides. (C) Wiley-VCH Verlag GmbH & Co.