RESOLUTION OF DIOLS WITH C2-SYMMETRY BY LIPASE-CATALYZED TRANSESTERIFICATION

S-Ethyl thiooctanoate was used as acyl donor in the transesterificatio n of 2,3-butanediol (1), 2,4-pentanediol (2), and 2,5-hexanediol (3), catalysed by a lipase from Candida antarctica. Mixtures of all stereoi somers were used as substrates in each case. 2,5-Hexanediol was transe sterified with high stereoselectivity and the (2S,5S)-2,5-hexanediol w as isolated in good yield with >99 % ee. The diester of (2R,5R)-2,5-he xanediol was formed in good yield and was hydrolysed to yield the (2R, 5R)-2,5-hexanediol of high enantiomeric excess (>99% ee). Similar resu lts were obtained for 2,4-pentanediol with >99% ee for both enantiomer s. The stereoselectivity for 2,3-butanediol was lower than for 2 and 3 , giving 89% ee for the R,R-enantiomer and 34% ee for the SS-enantiome r.