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。
Thiyl radical promoted iron-catalyzed-selective oxidation of benzylic sp<sup>3</sup> C–H bonds with molecular oxygen
A ligand-free iron-catalyzed method for the oxygenation of benzylic sp3 C–H bonds by molecular oxygen (1 atm) using a thiylradical as a cocatalyst has been developed. This transformation provides a facile access to amides, esters and ketones from readily accessible corresponding amines, ethers and alkanes. It features high regioselectivity, mild oxidative conditions and excellent functional group
A ligand-free and operationally simple copper-catalyzed aerobic benzylic sp3 C–H oxygenation was developed. The addition of tert-butyl hydroperoxide, either in a catalytic or stoichiometric amount, was key for activating stable C–H bonds under mild conditions to furnish the corresponding ketones or esters in moderate to excellent yield.
New Synthetic Methods for Seven- and Eight-Membered Cyclic Ethers Based on the Ring-Expansion Reactions of Hydroxy or Lithioxy Methoxyallenylisochroman Derivatives
The Pd(0)-catalyzed ring-expansion reactions of hydroxy methoxyallenyl-4,4-dialkylisochroman derivatives in the presence of P(o-tolyl) 3 proceeded smoothly via hydropalladation to give 3-benzoxepan-1-one derivatives in high yields. Treatment of isochroman-1-one derivatives with lithio methoxyallene followed by quenching the reaction with water furnished 3-benzoxocan-6-one derivatives in good yields
Enzymatic Baeyer-Villiger Oxidation of Benzo-Fused Ketones: Formation of Regiocomplementary Lactones
作者:Ana Rioz-Martínez、Gonzalo de Gonzalo、Daniel E. Torres Pazmiño、Marco W. Fraaije、Vicente Gotor
DOI:10.1002/ejoc.200900084
日期:2009.5
Baeyer-Villiger monooxygenases (BVMOs) are enzymes that are known to catalyse the Baeyer-Villigeroxidation of ketones in aqueous media using O(2) as oxidant. Herein, we describe the oxidation of a set of diverse benzo-fusedketones by three different BVMOs in both aqueous and non-conventional reaction media. Most of the tested ketones, for example, 1-tetralone and 1- and 2-indanone, were converted
Baeyer-Villiger 单加氧酶 (BVMO) 是已知的酶,它们使用 O(2) 作为氧化剂在水性介质中催化 Baeyer-Villiger 氧化酮。在此,我们描述了在水性和非常规反应介质中由三种不同的 BVMO 氧化一组不同的苯并稠合酮。大多数测试的酮,例如 1-四氢萘酮和 1- 和 2-茚满酮,都被使用的一种生物催化剂转化。通过在相对较高的 pH 值下进行氧化反应和添加有机助溶剂,可以提高催化效率。一个引人注目的观察结果是,当使用两种不同的 BVMO 氧化一系列 1-茚满酮时,获得了绝对和互补的区域选择性。4-羟基苯乙酮单加氧酶 (HAPMO) 对 1-茚满酮的转化导致预期的内酯 3,4-二氢香豆素的形成。相比之下,通过使用苯丙酮单加氧酶突变蛋白 (M-PAMO),1-茚满酮的转化导致仅形成意想不到的内酯,即 1-异色满酮。This illustrates that by the