Flavin Nitroalkane Oxidase Mimics Compatibility with NOx/TEMPO Catalysis: Aerobic Oxidization of Alcohols, Diols, and Ethers
作者:Pawan Thapa、Shan Hazoor、Bikash Chouhan、Thanh Thuy Vuong、Frank W. Foss
DOI:10.1021/acs.joc.0c01013
日期:2020.7.17
and inexpensive source for catalytic NO2 for aerobic TEMPO oxidations of alcohols, diols, and ethers. Alcohols were oxidized to aldehydes or ketones, cyclic ethers to esters, and terminal diols to lactones. In situ trapping of NOx and formaldehyde suggest an oxidative Nef process reminiscent of flavoprotein nitroalkane oxidasereactivity, which is achieved by relatively stable 1,10-bridged flavins
仿生黄素有机催化剂将硝基甲烷氧化为甲醛和NO x,为乙醇,二醇和醚的需氧TEMPO氧化提供了一种相对无毒,无苛刻且廉价的催化NO 2来源。醇被氧化成醛或酮,环醚被氧化成酯,末端二醇被氧化成内酯。NO x和甲醛的原位捕集表明氧化Nef过程使人联想到黄素蛋白硝基烷氧化酶的反应性,这是通过相对稳定的1,10-桥联黄素实现的。无金属的黄素/ NO x / TEMPO催化循环具有独特的相容性,尤其是与其他Nef和NO x相比生成过程,并显示出黄素催化亚砜形成的选择性。脂肪族醚通过这种方法被氧化,如(-)-氨氧化物转化为(+)-香紫苏内酯所证明的。
Synthesis of Chiral 3-Alkyl-3,4-dihydroisocoumarins by Dynamic Kinetic Resolutions Catalyzed by a Baeyer−Villiger Monooxygenase
作者:Ana Rioz-Martínez、Gonzalo de Gonzalo、Daniel E. Torres Pazmiño、Marco W. Fraaije、Vicente Gotor
DOI:10.1021/jo902519j
日期:2010.3.19
Baeyer−Villigermonooxygenases have been tested in the oxidation of racemic benzofused ketones. When employing a single mutant of phenylacetone monooxygenase (M446G PAMO) under the proper reaction conditions, it was possible to achieve 3-substituted 3,4-dihydroisocoumarins with high yields and optical purities through regioselective dynamic kinetic resolution processes.
A g-C<sub>3</sub>N<sub>4</sub>-based heterogeneous photocatalyst for visible light mediated aerobic benzylic C–H oxygenations
作者:Pengxin Geng、Yurong Tang、Guanglong Pan、Wentao Wang、Jinchuan Hu、Yunfei Cai
DOI:10.1039/c9gc02870f
日期:——
A metal-free heterogeneousphotocatalytic system has been developed for highly efficient benzylic C–H oxygenations using oxygen as an oxidant. This visible light mediated oxidation reaction utilizes graphitic carbonnitride (g-C3N4) as a recyclable, nontoxic and low cost photocatalyst. Mild reaction conditions allow for the generation of synthetically and biologically valued isochromannones, phthalides
已开发出一种无金属的非均相光催化系统,用于使用氧气作为氧化剂的高效苄基CH氧化。这种可见光介导的氧化反应利用石墨碳氮化物(gC 3 N 4)作为可回收,无毒且低成本的光催化剂。温和的反应条件可从易于获得的烷基芳族前体中以高收率生成合成和生物学上有价值的异苯并二氢醌,邻苯二甲酸,异喹啉酮,异吲哚啉酮和氧杂蒽。gC 3 N 4的异质性催化系统可轻松回收和循环利用,并可多次使用而不会损失活性。通过在生物活性和具有药物价值的靶标合成中的应用,进一步证明了这种“绿色”方法的综合效用。
α-Angelica lactone catalyzed oxidation of benzylic sp<sup>3</sup> C–H bonds of isochromans and phthalans
作者:Thanusha Thatikonda、Siddharth K. Deepake、Pawan Kumar、Utpal Das
DOI:10.1039/d0ob00729c
日期:——
efficient benzylic C–H oxygenations of cyclic ethers using oxygen as an oxidant. This oxidation reaction utilizes α-angelica lactone as a low cost/low molecular weight catalyst. The optimized reaction conditions allow the synthesis of valued isocoumarins and phthalides from readily available precursors in good yields. Mechanistic studies indicate that the reaction pathway likely involves a radical process
The reactivity of an electronicallytunednitroxylradicalcatalyst for the oxidation of cyclic benzylic ethers has been investigated. The oxidation of phthalan resulted in oxidative cleavage of the saturated ring to give an aromatic dialdehyde. Additionally, oxidation of isochromans afforded isochromanones, which are often seen in natural products, in a rapid manner.