Reported herein is a visible‐light‐mediated radical approach to the α‐alkylation of ketones. This method exploits the ability of a nucleophilic organocatalyst to generate radicals upon SN2‐based activation of alkyl halides and blue light irradiation. The resulting open‐shell intermediates are then intercepted by weakly nucleophilic silyl enol ethers, which would be unable to directly attack the alkyl
Generation of<i>β</i>-Carbonyl Radicals from Cyclopropanol Derivatives by the Oxidation with Manganese(III) 2-Pyridinecarboxylate and Their Reactions with Electron-Rich and -Deficient Olefins
Various β-carbonyl radicals are generated oxidatively from cyclopropanol derivatives by the use of manganese(III) 2-pyridinecarboxylate (Mn(pic)3). These β-carbonyl radicals react with electron-rich olefins such as conjugated silyl enol ethers, a ketene thioacetal, a ketene dithioacetal, and a vinyl ether intermolecularly to give crossed-addition products in good yield. Furthermore, the combined use
Visible-lightphotoredoxcatalysis has been utilized in a new multicomponent reaction forming β-functionalized δ-diketones under mild conditions in an operationally convenient manner. Single-electron reduction of in situ generated carboxylic acid derivatives forms acyl radicals that react further via 1,2-acylalkylation of olefins in an intermolecular, three-componentscascade reaction, giving valuable
Copper-Catalyzed Fluoroolefination of Silyl Enol Ethers and Ketones toward the Synthesis of β-Fluoroenones
作者:Yanlin Li、Jing Liu、Shuang Zhao、Xuzhao Du、Minjie Guo、Wentao Zhao、Xiangyang Tang、Guangwei Wang
DOI:10.1021/acs.orglett.7b03700
日期:2018.2.16
A general and facile synthetic method for β-fluoroenones from silylenolethers or ketones, with a copper–amine catalyst system, has been developed. The reaction proceeded by a tandem process of difluoroalkylation–hydrolysis–dehydrofluorination. This method is characterized by high yields, excellent Z/E ratios, a low-cost catalyst, and a broad substrate scope. The synthetic potential of β-fluoroenones
Iron-Catalyzed Highly Enantioselective Addition of Silyl Enol Ethers to α,β-Unsaturated 2-Acyl Imidazoles
作者:Jinhu Wei、Jie-Sheng Huang、Chi-Ming Che
DOI:10.1021/acs.orglett.1c02699
日期:2021.9.3
FeII(N4) complex (N4 = (R,R)-N,N′-bis(2-isopropylquinolin-8-yl)-1,2-diphenylethane-1,2-diamine) was developed for the asymmetric conjugate addition of silyl enol ethers, including both acyclic ones and cyclohexenone-derived ones, to α,β-unsaturated 2-acyl imidazoles. This FeII complex is an effective chiral Lewis acid and was applied in the synthesis of an array of chiral 1,5-dicarbonyl synthons and cyclohexenone
开发了手性 Fe II (N4) 配合物 (N4 = ( R , R )- N , N '-bis(2-isopropylquinolin-8-yl)-1,2-diphenylethane-1,2-diamine) 用于不对称甲硅烷基烯醇醚(包括无环和环己烯酮衍生的)与 α,β-不饱和 2-酰基咪唑的共轭加成。这种 Fe II 配合物是一种有效的手性路易斯酸,用于合成一系列手性 1,5-二羰基合成子和环己烯酮衍生物,具有高产率和对映选择性(高达 99% ee)。