A mechanism of asymmetric amplification, i.e., chemical reaction in which enantiomeric excess, ee, of a product is higher than that of chiral auxiliary for catalyst, was investigated. The reaction rate and the ee of the product differed significantly when the order of reagent addition was changed. A kinetic model formulated to explain this phenomenon predicted that the ee of the product should vary during the reaction. Our experimental investigation indeed found the variation of ee predicted by this theoretical model. There has been no previous report observing such a variation in ee during asymmetric amplification and a different ee produced by changing the order of reagent addition. (c) 2005 Elsevier B.V. All rights reserved.