Easy separation of optically active products by enzymatic hydrolysis of soluble polymer-supported substrates

The easy separation of optically active compounds from enzymatic kinetic resolution products by simple precipitation using poly(ethylene glycol)(PEG)-supported carbonates is disclosed. The water-soluble substrate was prepared by the immobilization of (±)-1-phenylethanol onto a middle-molecular weight (av Mw 5000) monomethoxy PEG (MPEG) through a carbonate linker. The enantioselective hydrolysis using Lipase from porcine pancreas (PPL; Type II, Sigma) in a mixed solvent (hexane/buffer = 9:1) proceeded to afford the corresponding optically active compounds. In this system, the separation of the products was achieved by a simple procedure without laborious column chromatography. A hydrophobic spacer between the MPEG moiety and the carbonate linker affected both the reactivity and enantioselectivity, and the substrate with a phenylethyl spacer was hydrolyzed with the highest enantioselectivity (E value = 270).