Enzymatic Resolution on Ionic Acylating Agents

Significance

A one-pot process for the resolution and separation of both enantiomers of sec-alcohols rac-1 via two consecutive enzymatic transesterifications with lipase B from Candida antarctica 2 (CALB) is reported. The separation is based on the temporal attachment of one of the enantiomers (R)-1 to imidazolium ionic acylating agent 3 in ionic liquid 4 ([bmim][PF₆]). Due to this attachment by enantioselective transesterification, the free enantiomer (S)-1 can be isolated by simple extraction with organic solvents. Subsequently, a second transesterification with ethanol releases the attached enantiomer (R)-1 and regenerates the reaction mixture of enzyme 2, ionic acylating agent 3, and ionic liquid 4 for reuse.