Combination Strategy Using Pure Enzymes and Whole Cells as Biocatalysts for the Preparation of 2‐Hydroxyesters and Lactones from 2‐Oxoglutaric Acid.

Abstract

Acid. -The title compounds are prepared in two consecutive biocatalytic steps. The first step involves the lipase catalyzed esterification of oxoglutaric acid (I). The second step involves the reduction of the resulting esters by use of fresh or freeze-dried yeast-like cells of Mucor rouxii. By use of freeze-dried cells, either hydroxyesters or lactones are formed, depending on the length of the alkyl chain in the ester. -(RUSTOY, E. M.; PEREYRA, E. N.; MORENO, S.; BALDESSARI*, A.; Tetrahedron: Asymmetry 15

Lipase-catalyzed synthesis of medium- and long-chain diesters of 2-oxoglutaric acid

“…This shows that an E/S ratio of 2 was enough for CALB catalysis, giving the product 2e in quantitative yield. Previous work on the esterifi cation of 2-oxoglutaric acid with short-chain alcohols used an E/S ratio of 5, but here CALB worked optimally at a lower ratio (Rustoy & Baldessari 2004). In the enzymatic esterifi cation of 1 with short-chain alcohols the alcohol could be used as solvent and esterifying agent, but with the longchain alcohols used to prepare 2a -2e , an auxiliary solvent was necessary to carry out the reaction.…”

“…Signal assignments were made by comparison of the data with previous reports (Rustoy & Baldessari 2004;Singh et al 2007).…”

“…In our laboratory lipases have been applied as catalysts for esterifi cation and transesterifi cation reactions involving fatty acids (Rustoy & Baldessari 2005;Monsalve et al 2009;Quintana & Baldessari 2009) and dicarboxylic acids (Monsalve et al 2008). Among them, lipase-catalyzed esterifi cation of 2-oxoglutaric acid with short-chain alcohols allowed us to obtain a series of dialkyl 2-oxoglutarates, which by microbial reduction afforded 2-hydroxyesters and γ -butyrolactones (Rustoy & Baldessari 2004).…”