Addressing the challenging field of chemoenzymatic dynamic kinetic resolution (DKR) of tertiary alcohols, for which so far only one example exists in the literature, we combined biocatalytic esterification and oxovanadium-catalyzed racemization, operating both steps in two different compartments of one reactor. The compartmentalization of the two heterogeneous catalysts, namely, immobilized lipase A from Candida antarctica (CAL-A) or its mutant and oxovanadium species on mesoporous silica, was achieved using a polydimethylsiloxane thimble, avoiding contact of the oxovanadium with water, thus maintaining the catalyst's activity and thereby successfully improving the efficiency of the DKR. Utilizing the immobilized double mutant CAL-A V278S + S429G, the ester was obtained in 62% yield with excellent enantiomeric excess of >99% ee.
Keywords: chemoenzymatic one-pot process; compartmentalization; dynamic kinetic resolution; enzyme catalysis; lipase A from Candida antarctica; tertiary alcohol.