Microbiological transformations. Part 45: A green chemistry preparative scale synthesis of enantiopure building blocks of Eliprodil: elaboration of a high substrate concentration epoxide hydrolase-catalyzed hydrolytic kinetic resolution process

The enantioselective hydrolysis of racemic para-chlorostyrene oxide 2 following a typical ‘green chemistry’ procedure based on the use of two different Epoxide Hydrolases is described. This allows the preparation of both enantiomers of 2 in very high enantiomeric purity. Furthermore, using a ‘one-pot’ sequential bi-enzymatic strategy enabling to overcome the 50% yield limitation intrinsic to any resolution process, rac-2 could be transformed into nearly enantiopure (R)-3 with an overall yield as high as 93%. The methodology developed was based on the use of a biphasic reactor at high substrate concentration, which is highly desirable for any potential industrial process. The obtained chirons are valuable building blocks for the synthesis of various biologically active targets, like (R)-Eliprodil.