Enzyme-Catalyzed Kinetic Resolution of 1,3-anti-Diol Monoesters - Efficient Preparation of Enantiomerically Highly Enriched and Unsymmetrically Substituted 1,3-anti-Diols

Candida antarctica Lipase B (CALB) catalyzed the highly enantioselective acetylation of 1,3‐anti‐diol monoesters which have been obtained through a zirconium‐catalyzed aldol‐Tishchenko reaction. The product 1,3‐anti‐diol diesters were formed in yields close to 50 % and >98 % ee. Separation from the unreactive enantiomers and subsequent hydrolysis furnished both enantiomers of unsymmetrically substituted 1,3‐anti‐diols in high optical purities. Alternatively, the kinetic resolution process can be performed on the free 1,3‐anti‐diols even more rapidly with equally good results. A slow acyl migration during the reaction slightly deteriorated the enantiomeric excess of the unreactive enantiomers. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)