Synthesis of Longhorn Beetle Pheromone Components by Proline-Mediated α-Hydroxylation of Alkyl Ketones
作者:Viviana Lucía Heguaburu、Hugo do Carmo、María Eugenia Amorós、Andrés González
DOI:10.1055/a-1541-4939
日期:2021.12
The stereoselective synthesis of several components of the aggregation pheromones of numerous longhorn beetle species is described. These attractants consist of 3-hydroxy-2-alkanones and 2,3-alkyldiols with chain lengths varying from six to ten carbons. The 3R- and 3S-series are generated by organocatalytic α-hydroxylation of alkyl ketones with nitrosobenzene in the presence of l- or d-proline, respectively
Deracemization of (±)-2,3-disubstituted oxiranes via biocatalytic hydrolysis using bacterial epoxide hydrolases: kinetics of an enantioconvergent process
作者:Wolfgang Kroutil、Martin Mischitz、Kurt Faber
DOI:10.1039/a704812b
日期:——
Asymmetric biocatalytichydrolysis of (±)-2,3-disubstituted oxiranes leading to the formation of vicinal diols in up to 97% ee at 100% conversion was accomplished by using the epoxide hydrolase activity of various bacterial strains. The mechanism of this deracemization was elucidated by 18OH2-labelling experiments using a partially purified epoxide hydrolase from Nocardia EH1. The reaction was shown
The kinetic resolution of several racemic syn-and anti-1,2-diols by enzymatic oxidation with Bacillus stearothermophilus diacetyl reductase is described. The enantiomerically pure (R,R)- and (R,S)-diols are recovered in almost quantitative yield. (C) 1998 Elsevier Science Ltd. All rights reserved.
Microbiological transformations. Part 39: Determination of the regioselectivity occurring during oxirane ring opening by epoxide hydrolases: a theoretical analysis and a new method for its determination
In the course of this work we have devised new equations as well as a new method allowing for the total determination of the regioselectivity occurring during biohydrolysis of a racemic epoxide by an epoxide hydrolase. This determination is achievable by simply studying the racemic epoxide as a substrate. The results showed that, depending on the enantioselectivity (E value) and the regioselectivity involved, the absolute configuration as well as the enantiopurity of the residual epoxide and of the formed diol appear to be highly variable. For a specific enzyme/substrate couple, the yield and enantiopurity of the less reactive (remaining) epoxide-and thus the possibility to prepare it in enantiopure form-exclusively depend upon the enzyme enantioselectivity. On the other hand, the ee of the formed diol (eep) depends upon the enantioselectivity and on the regioselectivity of the oxirane ring opening. A theoretical analysis based on the material balance, as well as several practical examples, are provided to illustrate the various possibilities of such biohydrolyses. (C) 1998 Elsevier Science Ltd. All rights reserved.
Banwell Martin G., Bridges Vanessa S., Dupuche Joseph R., Richards Sharon+, J. Org. Chem., 59 (1994) N 21, S 6338- 6343
作者:Banwell Martin G., Bridges Vanessa S., Dupuche Joseph R., Richards Sharon+