Comparison of the chiral recognition of prochiral substrates in the acetylation reaction by a novel lipase (CSL) from the yeast, Cryptococcus spp.S-2 with immobilized PPL Enzyme-catalyzed desymmetrization and asymmetrization of prochiral 2-substitute

摘要

In order to elucidate the nature of a novel lipase (CSL),isolated from the yeast Cryptococcus spp.S-2,in chiral recognition by comparison with that of immobilized PPL,the desymmetrization and asymmetrization of prochiral 2-phenyl-l,3-propanediol (la),2-benzyl-1,3-propanediol (1b),2-methyl-2-phenyl-l,3-propanediol (Ic),2-benzyl-2-methyl-l,3-propanediol (1d),2-ethyl-2-phenyl-l,3-propanediol (1e).and 2-benzyl-2-ethyl-l,3-propanediol (1f by acetylation was investigated.Acetylation of la with excess vinyl acetate by the CSL-enzyme catalyst gave the corresponding monoacetate 2a with high enantioselectivity (80% ee) in 46% yield.Very high levels of desymmetrization were observed in the tertiary systems of 1c-f,giving the corresponding monoacetates 2c-f.respectively,in >97%.In the desymmetrization of diols la.1c,1d,and 1f.the sense of chiral differentiation of CSL was opposite to that of immobilized porcine pancreatic lipase (PPL).