3-Alkoxyalkanoic esters are directly obtained in high yield from the reaction of acetals with Reformatsky reagents in the presence of titanium(IV) chloride or diethyl ether-boron trifluoride complex in dichloromethane. The reaction of ethyl 4-bromo-2-butenoate is regioselective, affording the product formed by attack on the 4-position. With chiral acetals as substrates, up to 84% enantiomerically enriched 3-hydroxyalkanoic esters can be prepared.
Novel anti-Prelog stereospecific carbonyl reductases from Candida parapsilosis for asymmetric reduction of prochiral ketones
作者:Yao Nie、Rong Xiao、Yan Xu、Gaetano T. Montelione
DOI:10.1039/c0ob00938e
日期:——
identified in Candida parapsilosis that consists of four open reading frames including three putative stereospecific carbonyl reductases (scr1, scr2, and scr3) and an alcohol dehydrogenase (cpadh). These newly identified three stereospecific carbonyl reductases (SCRs) showed high catalytic activities for producing (S)-1-phenyl-1,2-ethanediol from 2-hydroxyacetophenone with NADPH as the coenzyme. Together
gave ethyl (R)‐8‐chloro‐6‐hydroxyoctanoate, a key precursor for the synthesis of (R)‐α‐lipoic acid, in high space‐time yield (530 g L−1 d−1) and with excellent enantiomeric excess (>99%). This bioprocess was shown to be viable on a 10‐L scale. This method provides a greener and more cost‐effective method for the industrial production of (R)‐α‐lipoic acid.
从副产念珠菌中分离出了一种新型的还原酶(Cp AR2),该酶对ε-酮酯(8-氯-6-氧代辛酸乙酯)具有异常高的活性。共表达Cp AR2和葡萄糖脱氢酶基因的大肠杆菌细胞对8-氯-6-氧代辛酸乙酯的不对称还原产生了(R)-8-氯-6-羟基辛酸乙酯,这是合成(R)-α-的关键前体硫辛酸,时空产率高(530 g L -1 d -1),对映体过量极佳(> 99%)。该生物过程显示出在10 L规模上可行。这种方法为工业生产(R)-α-硫辛酸
Identification of a Robust Carbonyl Reductase for Diastereoselectively Building <i>syn</i>-3,5-Dihydroxy Hexanoate: a Bulky Side Chain of Atorvastatin
chiral precursor for the synthesis of the side chain pharmacophore of cholesterol-lowering drug atorvastatin. Herein, a robust carbonyl reductase (LbCR) was newly identified from Lactobacillus brevis, which displays high activity and excellent diastereoselectivity toward bulky t-butyl 6-cyano-(5R)-hydroxy-3-oxo-hexanoate (7). The engineered Escherichiacoli cells harboring LbCR and glucose dehydrogenase
叔丁基-6-氰基-(3 R,5 R)-二羟基己酸酯是一种先进的手性前体,用于合成降胆固醇药物阿托伐他汀的侧链药效团。在本文中,从短乳杆菌中新鉴定出一种强健的羰基还原酶(Lb CR),它对高密度的叔丁基6-氰基-(5 R)-羟基-3-氧代己酸叔丁酯具有很高的活性和非对映选择性(7)。具有Lb CR和葡萄糖脱氢酶(用于辅因子再生)的工程化大肠杆菌细胞被用作生物催化剂,用于不对称还原底物7。结果,多达300 g L –1的水不溶性底物以351 g L –1 d –1的时空产率被完全转化为相应的手性二元醇,de > 99.5%de,表明了巨大的潜力的Lb的CR对非常笨重和实际合成双向的畅销他汀类药物-手性3,5-二羟基羧酸侧链。
Asymmetric ketone reduction by a hyperthermophilic alcohol dehydrogenase. The substrate specificity, enantioselectivity and tolerance of organic solvents
作者:Dunming Zhu、Hiba T. Malik、Ling Hua
DOI:10.1016/j.tetasy.2006.10.042
日期:2006.11
asymmetric ketone reduction, the substrate specificity and enantioselectivity of an alcohol dehydrogenase from the hyperthermophilic archaeon Pyrococcus furiosus have been evaluated. This hyperthermophilic alcohol dehydrogenase catalyzes the reduction of various ketones including aryl ketones, α- and β-ketoesters. Interestingly, aryl ketones, phenyl-substituted α- and β-ketoesters were reduced to the