Zeolites significantly enhance the influence of chiral auxiliaries during p
hotochemical reactions. The generality of this phenomenon has been tested w
ith three independent examples. Chiral auxiliaries that lead to 1:1 mixture
s of diastereomers in solution give products in up to 80% diastereomeric ex
cess in the presence of faujasite type zeolites. (C) 2000 Elsevier Science
Ltd. All rights reserved.