Monosubstituted aromatic epoxides

Biohydrolytic kinetic resolution of racemic styrene oxide (rac-SO) catalyzed by Aspergillus niger LCP 521 (AnEH) an or Beauveria sulfurescens ATCC 7159 (fisEH). Using both fungi together led to an enantioconvergent production of (/ )-phenyl-1,2-ethanediol. 

8 EPOXIDE HYDROLASES AND THEIR APPLICATION IN ORGANIC SYNTHESIS 

Enantioconvergent biohydrolytic transformation of para hlorostyrene oxide using a bienzymatic process. The sequential use of Solanum tuberosum and Aspergillus niger EHs as biocatalysts led to the formation of enantiopure (/ )-para-chlorophenyl-1,2-diol, a chiral building block for the synthesis of (/ )-eliprodil. 

An enantioconvergent preparative-scale production of (] )-ffJcffl-chlorophenyl-1,2-ethanediol was described by Monterde et al. using the EH from S. tuberosum. The enzyme exhibited a low enantioselectivity (E-value of 6) in conjxmction witii an 

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Epoxide -> aliylic alcohol. Treatment of an oxirane with equimolar amounts of 1 and DBU in an aromatic solvent affords aliylic trimethylsilyl ethers in moderate yield. 2,2-Di-, tri-, and tetrasubstituted oxiranes, as well as oxides of cycloalkenes, react at 23° or below. 2,3-Di- and monosubstituted oxiranes do not react at this temperature these species react with 1 and DBU at 70-80° to give trimethylsilyl enol ethers. The reaction of epoxycyclooctane gives a product of transannular cyclization. In the case of epoxycyclohexane, the intermediate 2 has been isolated. 

In a continuation of some elegant studies on the synthesis of sterols, the non-enzymic cyclization of the monosubstituted epoxide (200) has been achieved, using boron trifluoride. Although the process occurs in very low yield, it does generate four rings and seven asymmetric centres, all possessing the relative configuration of non-aromatic steroids ... 

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