Epoxide hydrolase chemoenzymatic

Orru, R.V.A., Mayer, S.F., Kroutil, W. and Faher, K., Tetrahedron, Chemoenzymatic deracemi-sationof (+)-2,2-disubstituted oxiranes. 1998, 54, 859. Steinreiber, A., Hellstrdm, H., Mayer, S.F., Orru, R.V.A., Faber, K., Chemo-enzymatic enantio-convergent synthesis of C4-huilding blocks containing a fully substituted chiral carbon center using bacterial epoxide hydrolases. Synlett, 2001, 111. 

Scheme 15. Chemoenzymatic synthesis of a-bisabolol using fungal epoxide hydrolase...

Epoxide hydrolases are less used than lipases however, in recent years the synthesis of chiral diols with these biocatalysts has emerged as an excellent methodology to develop new and interesting chemoenzymatic processes [13],... 

Fig. 16. Bacterial epoxide hydrolase. Key steps of chemoenzymatic synthesis of (S)-frontalin...

Figure 11.2-16. Chemoenzymatic synthesis of (S)-(-)-frontalin using bacterial epoxide hydrolase.

Another example of an enantioconvergent transformation of racemic epoxides was reported by Faber and coworkers who employed a chemoenzymatic approach for the synthesis of optically enriched diols. They used an (S)-selective epoxide hydrolase from Nocardia sp. in connection with an add catalyzed hydrolytic step to convergently prepare (S)-diols 41 in good to excellent yields (71-98%) with enantiomeric excess values up to 99% (Scheme 9.13) [75]. 

R. V.A. Orm, W. Kroutil, K. Faber, Deracemization of (+/-)-2,2-disubstituted epoxides via enantioconvergent chemoenzymatic hydrolysis using Nocardia EHl epoxide hydrolase and sulfuric acid. Tetrahedron Lett. 38 (1997) 1753-1754. 

Kroutil, W., Osprian, L, Mischitz, M. and Faber, K. (1997b) Chemoenzymatic synthesis of (S)-(-)-frontalin using bacterial epoxide hydrolases. Synthesis, 156-158. 

---