Asymmetric Reduction of Activated Alkenes by Pentaerythritol Tetranitrate Reductase: Specificity and Control of Stereochemical Outcome by Reaction Optimisation
作者:Anna Fryszkowska、Helen Toogood、Michiyo Sakuma、Johnâ
M. Gardiner、Gillâ
M. Stephens、Nigelâ
S. Scrutton
DOI:10.1002/adsc.200900574
日期:2009.11
We show that pentaerythritol tetranitrate reductase (PETNR), a member of the ‘ene’ reductase old yellow enzyme family, catalyses the asymmetric reduction of a variety of industrially relevant activated α,β-unsaturated alkenes including enones, enals, maleimides and nitroalkenes. We have rationalised the broad substrate specificity and stereochemical outcome of these reductions by reference to molecular
我们显示季戊四醇四硝酸盐还原酶(PETNR),'烯'还原酶老黄色酶家族的成员,催化各种工业相关的活化α,β-不饱和烯烃包括烯酮,烯醛,马来酰亚胺和硝基烯烃的不对称还原。通过参考基于PETNR与2-环己烯酮4a的晶体复合物的酶-底物复合物的分子模型,我们合理化了这些还原反应的广泛的底物特异性和立体化学结果。产品的光学纯度是可变的(49–99%ee),具体取决于底物类型和取代基的性质。通常,对于立体定位中心在Cβ(> 99%ee的反应产物)观察到高对映体选择性)。不过,现有的在两种异构形式(例如,柠檬醛基板11A或硝基烯烃18 - 19A),减少的enantiodivergent当然E / Z -forms可能导致降低产品的enantiopurities。我们还证明,对于具有Cα立体定位中心的产品,其光学纯度差是由于非酶消旋作用。在与酮异佛尔酮3a的反应中,我们表明通过优化反应,特别是通过缩短