visible-light photoredox catalysis. A variety of tetraalkyl ammonium salts, bearing primary, secondary, and tertiary C-N bonds, undergo selective couplings with aldehydes/ketone and CO2. Notably, the in situ generated byproduct, trimethylamine, is efficiently utilized as the electron donor. Moreover, this protocol exhibits mild reaction conditions, low catalyst loading, broad substrate scope, good
两个亲电子试剂之间的交叉亲电子试剂偶联是在化学计量外部还原剂存在下生成 CC 键的有效且经济的方法。在此,我们报告了一种通过可见光光氧化还原催化实现第一个无外部还原剂的交叉亲电子偶联的新策略。各种带有伯、仲和叔 CN 键的四烷基铵盐与醛/酮和 CO2 进行选择性偶联。值得注意的是,原位生成的副产物三甲胺被有效地用作电子供体。此外,该协议表现出温和的反应条件、低催化剂负载、广泛的底物范围、良好的官能团耐受性和容易的可扩展性。机理研究表明,苄基自由基和阴离子可能是通过光催化产生的关键中间体,
Nickel-Catalyzed Cross-Coupling of Styrenyl Epoxides with Boronic Acids
作者:Daniel K. Nielsen、Abigail G. Doyle
DOI:10.1002/anie.201101191
日期:2011.6.27
Let's get multicatalytic! A Ni0 catalyst complexed with a biaryldialkyl monophosphine ligand facilitates CC bond formation between styrenylepoxides and aryl boronicacids (see scheme). X‐ray analysis of a catalytically active nickel/ligand complex supports a redox pathway involving CO bond activation. A variety of α‐substituted alcohols were generated with good reaction efficiency by a multicatalytic
and efficient visible light induced Meerwein hydration reaction of alkenes in aqueous medium using mpg-C3N4 as a recyclabe photocatalyst has been disclosed. This protocol provides a direct approach for the preparation of racemic alcohols via a free radical mechanism. Water acted as both a solvent and a reagent without any additives or co-solvents. The metal-free heterogeneous semiconductor is found
已经公开了使用mpg-C 3 N 4作为可回收的光催化剂,绿色和有效的可见光诱导的水性介质中烯烃的Meerwein水合反应。该协议提供了一种通过自由基机制制备外消旋醇的直接方法。在没有任何添加剂或助溶剂的情况下,水既充当溶剂又充当试剂。发现不含金属的异质半导体至少可以完全回收5次,而活性没有任何显着降低。Meerwein水合反应具有出色的底物范围,并以中等至高收率提供了所需的产物。此外,该反应可以在太阳光照射下进行,并且可用于大规模反应,并具有令人满意的结果。
作者:Hongyu Wang、Zhihui Wang、Guo Zhao、Velayudham Ramadoss、Lifang Tian、Yahui Wang
DOI:10.1021/acs.orglett.2c01286
日期:2022.5.27
bond formation reaction is achieved through electrochemical reduction of alcoholic phosphates or sulfonates with aldehydes or ketones. Alcohol derivatives of phosphates undergo single-electron reduction under electrochemical conditions followed by a spontaneous cleavage of the C–O bond with the exothermic loss of phosphate resulting in an alkyl radical species. Subsequently, radical intermediates are further
β‐Arylation of Racemic Secondary Benzylic Alcohols to Access Enantioenriched β‐Arylated Alcohols
作者:Wang Miao、Jinyu Zhang、Yanyan Yang、Weijun Tang、Dong Xue、Jianliang Xiao、Huaming Sun、Chao Wang
DOI:10.1002/anie.202306015
日期:2023.7.24
catalyst, the first example of β-arylation of secondary alcohols with aryl bromides has been developed via borrowing hydrogen catalysis enabled by an MPV type hydrogen transfer process. In addition, the enantioconvergent version of the reaction has also been realized under the catalysis of Pd and Ru, allowing for the transformation of racemic secondary alcohols into enantioenriched chiral alcohols with good