A photoredox and Brønsted acid synergistically catalyzed cross‐dehydrogenative C−Ocouplingreaction is developed in which isochroman peroxyacetals are formed through sp3 C−H bond peroxidation. The reported method is characterized by its extremely mild reaction conditions, excellent yields, and broad substrate scope. An oxocarbenium ion p‐chlorobenzenesulfonate was speculated to be the reactive intermediate
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。
DDQ-mediated Direct C(sp<sup>3</sup>)H Cyanation of Benzyl Ethers and 1,3-Diarylpropenes under Solvent- and Metal-free Conditions
作者:Shanshan Kong、Lingqiong Zhang、Xiaoli Dai、Lianzhi Tao、Chunsong Xie、Lei Shi、Min Wang
DOI:10.1002/adsc.201500096
日期:2015.8.10
A directcyanation of benzylethers and 1,3‐diarylpropenes with TMSCN was performed under solvent‐ and metal‐free conditions. This oxidative cross dehydrative coupling (CDC) reaction was promoted by 2,3‐dichloro‐5,6‐dicyano‐1,4‐benzoquinone (DDQ) and provided rapid access to a broad range of nitriles in good to excellent yields.
development of expeditious methods to synthesize these skeletons remains a challenging task. In this work, the catalyticcyclization of biomass-derived 2-furylcarbinols with an azide to form fused triazoles is described. This approach takes advantage of a single catalyst Yb(OTf)3 and operates via a furfuryl-cation-induced intramolecular [3 + 2] cycloaddition/furan ring-opening cascade.