A stereospecific cyclization catalyzed by an antibody.

A monoclonal antibody elicited by a transition-state analog that is representative of an intramolecular six-membered ring cyclization reaction acted as a stereospecific, enzyme-like catalyst for the appropriate substrate. Formation of a single enantiomer of a delta-lactone from the corresponding racemic delta-hydroxyester was accelerated by the antibody by about a factor of 170, which permitted isolation of the lactone in an enantiomeric excess of about 94 percent. This finding demonstrates the feasibility of catalytic-antibody generation for chemical transformations that require stereochemical control.