Enzymatic Lactonization Stategy for Enantioselective Synthesis of a Tetrahydrolipstatin Synthon.

A novel lipase-catalyzed protocol has been formulated for the simultaneous enantiocontrol of three stereogenic centers in a flexible acyclic system. This involved a porcine pancreatic lipase (PPL)-catalyzed delta-lactonization of a racemic 3,5-dihydroxy-2-alkyl ester to produce the lactone with high enantioselectivity (92.8%). The product lactone and its analogues are useful synthons for the asymmetric synthesis of various bioactive compounds, which include the potential anti-obesity compound, tetrahydrolipstatin.