Syntheses of Highly Oxygen-functionalized Derivatives of Dihydrodihydroxyphthalic Acid in Enantiomerically Enriched Forms.

Starting from dihydrodihydroxyphthalic acid (DDP), (1R, 2S, 5R, 6S)-(-)-3,4-bis(benzyloxymethyl)-5-hydroxy-8,8-dimethyl-6,8-dioxabicyclo[4.3.0]non-3-en-2-yl chloroacetate (>95%e.e.), a highly oxygen-functionalized derivative, was prepared by a combination of chemical and enzymatic reactions. The key step for asymmetrization was hydrolysis of the corresponding meso bis-chloroacetate with pig pancreatic lipase.