LIPASE-CATALYZED RESOLUTION OF ALPHA-HYDROXYMETHYL SULFONES - DETERMINATION OF ABSOLUTE-CONFIGURATION BY SEMIEMPIRICAL CALCULATION OF CD SPECTRA AND VERIFICATION BY X-RAY STRUCTURE-ANALYSIS

The Candida antarctica lipase catalyzed esterification of the hydroxym ethyl sulfones rac-1a and rac-1b led to the isolation of ent-la (92% e e) and Ib (greater than or equal to 99% ee), respectively, The acyloxy methyl sulfone ent-71 (greater than or equal to 99% ee) was obtained b y the Candida antarctica lipase catalyzed hydrolysis of rac-7a. Not on ly Candida antarctica lipase but also Pseudomonas cepacia lipase showe d the opposite enantiomer differentiation in the esterification of the methyl substituted alcohol rac-1a and the benzyl substituted alcohol rac-1b. The absolute configuration of ent-la and Ib was determined by measurement of their circular dichroism and the calculation of the CD spectra of la and Ib by semiempirical methods. The configurational ass ignment was verified by X-ray structure analysis of Ib and ent-7a. (C) 1997 Elsevier Science Ltd.