Effect of cyclodextrin on improvement of enantioselectivity in the reduction of ketopantolactone with baker's yeast.

Addition of beta-cyclodextrin improves enantioselectivity dramatically in the reduction of ketopantolactone mediated by baker's yeast. It has been found that the selectivity increases with the decrease in concentration of ketopantolactone in bulk solvent, and beta-cyclodextrin controls its effective concentration. The role of beta-cyclodextrin is discussed.