Preparative-scale pig liver esterase-catalyzed hydrolyses of five-membered ring meso-1,3-diesters are enantiotopically selective. While pro-S enantiotopic selectivity is exhibited in each case, the absolute configuration sense of the hydrolysis in the cyclopentyl series is opposite to that of both the tetrahydrofuranyl and tetrahydrothiophenyl diesters. The enantiomeric excess levels induced are in the 34–46% range.
Preparative-scale horse liver alcohol dehydrogenase-catalyzed oxidation of mesoexo- and endo-7-oxabicyclo[2.2.1]heptane diols provides a direct one-step route to enantiomerically pure chiral γ-lactones of the oxabicyclic series.
