First stereoselective acylation of a primary diol possessing a prochiral quaternary center mediated by lipase TL from Pseudomonas stutzeri

Abstract

The first described acylation of a primary diol possessing a prochiral quaternary center catalyzed by lipase TL from Pseudomonas stutzeri is described. Optimized conditions were designed by testing different experimental conditions on model substrates (cyclopentylmethanol, cyclohexylmethanol, cyclopentane-1,1-diyldimethanol or cyclohexane-1,1-diyldimethanol) to find best organic solvent, optimal acyl donor and temperature, as well as the optimal substrates/enzyme ratio. Lipase TL resulted the best biocatalyst, while vinyl butyrate as acylating agent and a mixture of isooctane/THF 8/2, (v/v) resulted the best experimental conditions. Under these conditions, reaction were monitorized by chiral HPLC (diffraction index detector). The enantiomeric excess in the acylation of target substrate, (tetrahydro-2H-pyran-2,2-diyl)dimethanol, was measured by derivatization of monoesters with Mosher's R-MTPA-Cl, which also was useful to determine the S absolute configuration of the major reaction product of the lipase-catalyzed monoacylation.