Enzyme-Mediated Preparation of Optically Active 1,2-Diols Bearing a Long Chain: Enantioselective Hydrolysis of Cyclic Carbonates

A new entry for the efficient preparation of optically active 1,2-diols having a long aliphatic chain via an enzymatic reaction is disclosed. PPL catalyzes the hydrolysis of a racemic five-membered cyclic carbonate, 4-(7-benzyloxy)heptyl-1,3-dioxolan-2-one (2a), with high enantioselectivity to produce the optically active (R)-2a and (S)-9-benzyloxynonane-1,2-diol (3a) in excellent yields. The reaction is applicable to the substrates with a longer chain (10-benzyloxydecyl (3b) and 13-benzyloxytridecyl group (3c)). Optically pure (S)-(+)-8-hydroxyhexadecanoic acid (1), a biologically active natural compound with a chiral long aliphatic part, is effectively synthesized starting from (R)-3-(7-benzyloxy)heptyl-2-oxirane (9), which is converted from both enantiomers of 3a.