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Enantioselective Bio‐Hydrolysis of Various Racemic and meso Aromatic Epoxides Using the Recombinant Epoxide Hydrolase Kau2
Author(s) -
Zhao Wei,
Kotik Michael,
Iacazio Gilles,
Archelas Alain
Publication year - 2015
Publication title -
advanced synthesis and catalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.541
H-Index - 155
eISSN - 1615-4169
pISSN - 1615-4150
DOI - 10.1002/adsc.201401164
Subject(s) - epoxide hydrolase , enantioselective synthesis , desymmetrization , biocatalysis , chemistry , epoxide , kinetic resolution , diol , hydrolysis , organic chemistry , enantiomer , substrate (aquarium) , enantiomeric excess , stereochemistry , enzyme , catalysis , reaction mechanism , biology , microsome , ecology
Abstract Epoxide hydrolase Kau2 overexpressed in Escherichia coli RE3 has been tested with ten different racemic and meso α,β‐disubstituted aromatic epoxides. Some of the tested substrates were bi‐functional, and most of them are very useful building blocks in synthetic chemistry applications. As a general trend Kau2 proved to be an extremely enantioselective biocatalyst, the diol products and remaining epoxides of the bioconversions being obtained – with two exceptions – in nearly enantiomerically pure form. Furthermore, the reaction times were usually very short (around 1 h, except when stilbene oxides were used), and the use of organic co‐solvents was well tolerated, enabling very high substrate concentrations (up to 75 g/L) to be reached. Even extremely sterically demanding epoxides such as cis ‐ and trans ‐stilbene oxides were transformed on a reasonable time scale. All reactions were successfully conducted on a 1 g preparative scale, generating diol‐ and epoxide‐based chiral synthons with very high enantiomeric excesses and isolated yields close to the theoretical maximum. Thus we have here demonstrated the usefulness and versatility of lyophilized Escherichia coli cells expressing Kau2 epoxide hydrolase as a highly enantioselective biocatalyst for accessing very valuable optically pure aromatic epoxides and diols through kinetic resolution of racemates or desymmetrization of meso epoxides.