Lactones 34 [1]. Application of alcohol dehydrogenase from horse liver (HLADH) in enantioselective synthesis of δ- and ɛ-lactones

The ability of horse liver alcohol dehydrogenase (HLADH) to the enantioselective oxidation of primary–primary, primary–secondary and primary-tertiary aliphatic 1,5- and 1,6-diols 1a–i was studied. No enantioselectivity of the transformations of primary–primary 1,6-diols 1a–d to ɛ-lactones 4a–d was observed. Regioselective oxidation of primary–secondary 1,6-diols 1e,f and 1,5-diols 1h,i afforded enantiomerically enriched ɛ-lactones 4e,f and δ-lactones 4h,i. ɛ-Lactones 4e,f were formed with higher enantiomeric excesses (e.e. = 85–99%). Enzymatic oxidation of primary–tertiary 1,6-diol 1g did not give lactone product.