Type II Flavin-Containing Monooxygenases: A New Class of Biocatalysts that Harbors Baeyer-Villiger Monooxygenases with a Relaxed Coenzyme Specificity
作者:Anette Riebel、Michael J. Fink、Marko D. Mihovilovic、Marco W. Fraaije
DOI:10.1002/cctc.201300550
日期:2014.4
type II FMOs follow a catalytic mechanism similar to that of other class B flavoprotein monooxygenases. A set of cyclobutanones and cyclohexanones were used to probe the regio‐ and enantioselectivity of all three recombinant monooxygenases. The biocatalysts readily accepted small cyclic ketones, which enabled the conversion of previously poorly accepted substrates by other monooxygenases (especially
Selective C−H Halogenation with a Highly Fluorinated Manganese Porphyrin
作者:Gang Li、Andrew K. Dilger、Peter T. Cheng、William R. Ewing、John T. Groves
DOI:10.1002/anie.201710676
日期:2018.1.26
functionalization of aliphatic molecules remains a challenge in organic synthesis. While radical chain halogenation reactions provide efficient access to many halogenated molecules, the use of typical protocols for the selective halogenation of electron‐deficient and strained aliphatic molecules is rare. Herein, we report selective C−H chlorination and fluorination reactions promoted by an electron‐deficient
Enantio- and stereocontrolled syntheses of (−)-semburin, (+)-N-benzoylmeroquinene aldehyde, (−)-antirhine, and (+)-isocorynantheol from common (+)-norcamphor
作者:Mitsuhiro Kawamura、Kunio Ogasawara
DOI:10.1016/0040-4039(95)00543-l
日期:1995.5
A general enantio- and stereocontrolled route to the representative secologanin natural products, (−)-semburin, (+)-N-benzoylmeroquinene aldehyde, (−)-antirhine, and (+)-isocorynantheol, has been developed starting from (+)-norcamphor as a common chiral building block.
substrates with hydrogen peroxide and achieve good conversions and selectivities. Chemoselective oxidations toward unsaturated lactones are obtained from unsaturated ketones. The Lewis acidity and the catalytic performance of the grafted Sn(IV) centers are very similar to the directly synthesized Sn-MCM-41, but lower than those of the Sn-Beta zeolite.
已使用不同的R n SnX 4- n前体将Sn(IV)中心嫁接到中孔MCM-41上。为了成功地掺入锡,一个或两个烷基取代基是有益的。煅烧的样品能够活化羰基键以引起亲核攻击,这可以通过原位红外光谱显示出来。所得的催化剂对于用过氧化氢对各种底物的拜耳-维利格氧化具有活性,并具有良好的转化率和选择性。由不饱和酮获得向不饱和内酯的化学选择性氧化。接枝的Sn(IV)中心的路易斯酸度和催化性能与直接合成的Sn-MCM-41非常相似,但低于Sn-Beta沸石。
Baeyer–Villiger oxidation of cyclic ketones using Fe containing MCM-48 cubic mesoporous materials
作者:Hariharaputhiran Subramanian、Elizabeth G. Nettleton、Sridhar Budhi、Ranjit T. Koodali
DOI:10.1016/j.molcata.2010.07.003
日期:2010.9
Iron containing cubic mesoporous MCM-48 materials were prepared by a modified Stober synthesis method. These materials were characterized by powder X-ray diffraction (XRD). nitrogen isotherms, diffuse-reflectance UV-Vis spectroscopy, and electron microscopy. These materials exhibited high catalytic activity towards the Baeyer-Villiger oxidation of cyclic ketones using benzaldehyde and molecular oxygen. The Fe-MCM-48 mesoporous materials showed excellent recyclability and the integrity of the cubic phase was preserved after the catalytic activity. (C) 2010 Elsevier B.V. All rights reserved.