Easy preparation of enantiomerically enriched heteroaromatic alcohols through lipase-catalyzed acylation with succinic anhydride under unconventional activation.

Abstract

This study reports the lipase-catalyzed resolution of heteroaromatic secondary alcohols by succinic anhydride under different activation conditions by convenient procedure with succinic anhydride. The effects of succinic anhydride and the nature of the heteroatom are discussed in standard conditions in the kinetic resolution with lipases. The results recorded under microwave activation and ultrasonication is compared. (R)-4-chromanol was obtained in optically pure form (ee > 99%) with a high selectivity E > 200 by Pseudomonas cepacia lipase (PCL) in diethyl ether, using microwave radiation and under ultrasonication. The reaction time is reduced compared to the conventional heating with a better control of the selectivity of the lipase PCL. A significant effect of the nature of the heteroatoms on the reactivity and selectivity of the lipase with succinic anhydride has been disclosed, regardless the conditions of activation. This method proved to be clean, fast, interesting alternative, and facilitates the use of a cyclic anhydride, by microwave or ultrasound especially with secondary alcohols. The process is a valuable prerequisite for the preparative scale production of enantiomerically heteroaromatic alcohols in sustainable chemistry.