- Chemoenzymatic deracemization of (±)-2,2-disubstituted oxiranes
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The preparation of vicinal diols in up to 98% e.e. and 98% yield from the corresponding (±)-2,2-disubstituted epoxides was achieved via an enantioconvergent two-step hydrolysis: Thus, enantioselective enzymatic hydrolysis of the (S)-epoxide proceeded with retention of configuration furnishing the corresponding (S)-diol. In a subsequent step, the remaining (R)-oxirane was hydrolyzed during workup under acid catalysis with complete inversion of configuration yielding the (5)-diol. A detailed study of the latter reaction revealed that the experimental conditions have to be carefully chosen with respect to (i) nature of the acid, (ii) the solvent, and (iii) its water content to avoid racemization.
- Orru, Romano V. A.,Mayer, Sandra F.,Kroutil, Wolfgang,Faber, Kurt
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p. 859 - 874
(2007/10/03)
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- Highly Selective asymmetric hydrolysis of 2,2-disubstituted epoxides using lyophilized cells of Rhodococcus sp. NCIMB 11216
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(+/-)-2-Methyl-2-alkyl epoxides have been resolved by biocatalytic hydrolysis employing lyophilized cells of Rhodococcus sp.NCIMB 11216.The reaction has been shown to proceed with retention of configuration leading to (S)-1,2-diols and (R)-epoxides with excellent selectivities (E > 100).
- Wandel, Ute,Mischitz, Martin,Kroutil, Wolfgang,Faber, Kurt
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p. 735 - 736
(2007/10/02)
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