Abstract An efficient enzymatic resolution of 7, 7-disubstituted 1, 4, 5, 6-tetrachlorobicyclo [2.2. 1] hept-5-en-2-ols was accomplished by means of lipase AY-30 from Candida cylindracea in toluene. When acid anhydrides were used as acyl donors, the enantioselectivity was found to depend strongly on the reaction conditions: Whereas low selectivity (E< 20) was observed without precautions taken in order to remove the co- ...