초록
<P>Novel and efficient one-pot enzymatic and chemo-enzymatic synthetic methods are developed for the asymmetric <I>trans</I>-dihydroxylations of cyclic olefins 1a and 1b<I>via</I> sequential epoxidation and hydrolysis. The Novozym 435<SUP>®</SUP>-mediated epoxidation of cyclohexene 1a and subsequent hydrolysis of the intermediate cyclohexene oxide 2a with resting cells of <I>Sphingomonas</I> sp. HXN-200 in one-pot gave (1<I>R</I>,2<I>R</I>)-cyclohexane diol 3a in 84% ee and 95% conversion. <I>trans</I>-Dihydroxylation of <I>N</I>-benzyloxycarbonyl 3-pyrroline 1b with the same enzymatic system gave the corresponding (3<I>R</I>,4<I>R</I>)-<I>N</I>-benzyloxycarbonyl-3,4-dihydroxy-pyrrolidine 3b in 93% ee and 94% conversion. In the one-pot chemo-enzymatic system, epoxidation of <I>N</I>-benzyloxycarbonyl 3-pyrroline 1b by <I>m</I>-CPBA and subsequent hydrolysis of epoxide intermediate 2b with resting cells of <I>Sphingomonas</I> sp. HXN-200 gave the <I>trans</I>-diol (3<I>R</I>,4<I>R</I>)-3b in 92% ee and 94–97% conversion. While the <I>trans</I>-dihydroxylation of cyclohexene 1a to (1<I>R</I>,2<I>R</I>)-cyclohexane diol 3a is reported for the first time, the <I>trans</I>-dihydroxylation of <I>N</I>-benzyloxycarbonyl 3-pyrroline 1b to (3<I>R</I>,4<I>R</I>)-3b with such an enzymatic or chemo-enzymatic system afforded a much higher product concentration than the same reaction with the system using a microorganism containing the two necessary enzymes. The developed one-pot enzymatic and chemo-enzymatic systems for the asymmetric <I>trans</I>-dihydroxylation of olefins are new, easy to prepare, adjust and operate, are high yielding, complementary to Sharpless asymmetric dihydroxylation and particularly useful for the asymmetric synthesis of cyclic <I>trans</I>-diols.</P> <P>Graphic Abstract</P><P>Asymmetric <I>trans</I>-dihydroxylation of olefins was achieved <I>via</I> sequential enzymatic or chemo-enzymatic reactions in one-pot to prepare cyclic <I>trans</I>-diols in high ee.<BR><IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c1gc15501f'><BR></P>