The Esterase Catalysed Resolution of Lactones and Spirodilactone

The pig liver esterase catalysed hydrolysis of spirodilactone and γ-phenyl-γ-butyrolactone gives optically active products (>90% e.e., after 50% reaction). However, the similarly substituted acyclic ester analogues of the lactone do not exhibit enantioselectivity suggesting that the acylation step shows the selectivity. Racemic spirodilactone can be converted, in principle, entirely into one of its enantiomers.