Electronic Effect-Guided Rational Design of Candida antarctica Lipase B for Kinetic Resolution Towards Diarylmethanols

Herein, we developed an electronic effect-guided rational design strategy to enhance the enantioselectivity of Candida antarctica lipase B (CALB) mutants towards bulky pyridyl(phenyl)methanols. Compared to W104A mutant previously reported with reversed S-stereoselectivity toward sec-alcohols, three mutants (W104C, W104S and W104T) displayed significant improvement of S-enantioselectivity in the kinetic resolution (KR) of various phenyl pyridyl methyl acetates due to the increased electronic effects between pyridyl and polar residues. The electronic effects were also observed when mutating other residues surrounding the stereospecificity pocket of CALB, such as T42A, S47A, A281S or A281C, and can be used to manipulate the stereoselectivity. A series of bulky pyridyl(phenyl) methanols, including S-(4-chlorophenyl)(pyridin-2-yl) methanol (S-CPMA), the intermediate of bepotastine, were obtained in good yields and ee values.

Automated summary

Using an electronic effect-guided rational design strategy, significant improvement of enantioselectivity towards bulky pyridyl(phenyl)methanols is achieved in CALB mutants, leading to successful kinetic resolution of various phenyl pyridyl methyl acetates with good yields and ee values.