Enhancement of enzyme activity and enantioselectivity by cyclopentyl methyl ether in the transesterification catalyzed by Pseudomonas cepacia lipase co-lyophilized with cyclodextrins

The solvent effects of cyclopentyl methyl ether (CPME) on the reaction rates and enzyme enantioselectivity in the enantioselective transesterifications of racemic 6-methyl-5-hepten-2-ol (racemic sulcatol: SUL) and racemic 2,2-dimethyl-1,3-dioxolane-4-methanol (racemic solketal: SOL) with a series of enol esters catalyzed by Pseudomonas cepacia lipase co-lyophilized with cyclodextrins (alpha-, beta-, gamma-, partially methylated beta-, and 2,3,6-tri-O-methyl-beta-cyclodextrin: alpha CyD; beta CyD; gamma CyD; Me-1.78 beta CyD; Me-3 beta CyD) were investigated and compared with those in diisopropyl ether (IPE). In the case of SUL, enzyme activities of the co-lyophilizate with Me-1.78 beta CyD in CPME were lower than those in IPE with every acyl source, however, the absolute enantiopreference was shown in the transesterification with vinyl butyrate (VBR) in IPME. When the substrates were SOL and VBR, the enzyme activities in CPME were greatly enhanced as high as 1.6-9.8-fold, while the enantioselectivities in CPME were comparable to those in IPE.