Stereo- and enantioselectivity of the soluble epoxide hydrolase-catalysed hydrolysis of (±)- cis-dialkyl substituted oxiranes

Abstract

Both enantiomers of cis-(±)-2,3-epoxyheptane ( 1a), cis-3,4-epoxyheptane ( 1b), cis-3,4-epoxynonane ( 1c) cis-3,4-epoxynonane-1-ol ( 1d) and cis-1-methoxy-3,4-epoxynonane ( 1e) are transformed into the corresponding threo-diols 2a-e by soluble epoxide hydrolase catalysed hydrolysis. The reaction proceeds with a substrate and product enantioselection, which is highly dependent on the substituents at the oxirane ring. Whereas the hydrolysis of racemic 1a shows practically no enantioselection, that of its isomer 1b, gives after complete hydrolysis, in a stereoconvergent way, the corresponding threo-diol (3R,4R)- 2b. On the other hand, the hydrolysis of epoxides 1c-e progress with a fairly good ( 1c and 1e) or complete ( 1d) substrate enantioselection to give racemic ( 2c) or, in a stereoconvergent way, optically enriched ( 2e) or pure ( 2d) diols. Significant differences were observed from the previous results of the hydrolysis of the same substrates with microsomal epoxide hydrolase.