Lipase-catalyzed two-step transesterification of diols: Estimation of selectivities

Abstract

Reactions for the lipase-catalyzed kinetic resolution of chiral diols or the desymmetrization of achiral meso-diols involve two alternative routes, each of which contains two steps. During such reactions, up to four different nucleophiles compete to attack the acyl-enzyme intermediate of the catalytic cycle. The selectivities of the lipase for these different nucleophiles determines the success of the desymmetrization or resolution process and are important parameters for time-based mathematical models of these processes. Current methods for estimating these selectivities are not sufficiently accurate. In the current work, we develop a new approach to determining selectivities in lipase-catalyzed desymmetrization or resolution reactions with diols. The method is based on a model in which the only parameters are selectivities. We demonstrate the application of the method using literature data for three case studies of increasing complexity: (i) the two-step acetylation of phlorizin; (ii) the kinetic resolution of racemic 1,3-butanediol and (iii) the two-step desymmetrization of a meso-diol to produce a monoacetylated diol that is a key intermediate in the synthesis of biotin. We demonstrate the advantages of our estimation method over previously proposed estimation methods. The selectivities estimated by our method will be important parameters in models describing the desymmetrization and resolution of diols.