Biocatalytic Access to Chiral Polyesters by an Artificial Enzyme Cascade Synthesis

Chiral polyesters in general can be employed for versatile biomedical purposes, but in vitro enzyme catalyzed biocatalytic routes by a multiple-step cascade to make these functional biodegradable chiral polyesters have been hardly investigated. Recently, we developed an artificial three-step enzymatic cascade synthesis by combining an alcohol dehydrogenase (ADH), a Baeyer-Villiger monooxygenase (BVMO) and a lipase (CAL-A). Here, we extended this cascade for the synthesis of chiral methyl-substituted oligo-ε-caprolactone derivatives to achieve both, the generation of chirality in a monomer and the subsequent polymerization. Several substrates were examined and provided access to functionalized chiral compounds in high yields (up to >99 %) and optical purities (up to >99 % ee). By subsequent enzymatic enantioselective ring opening of the enantiopure monomers, oligomeric lactones were successfully synthesized. Rotate me! By combining three enzymes (LK-ADH, CHMO, CAL-A), which are evolutionary not connected, to an artificial cascade, optically active chiral oligomers can be synthesized from nonchiral or racemic methyl-substituted cyclohexanol derivatives.