Transition‐Metal‐Promoted Direct C−H Cyanoalkylation and Cyanoalkoxylation of Internal Alkenes
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Radical C−C Bond Cleavage of Cycloketone Oxime Esters
作者:Jiang Lou、Yuan He、Yunlong Li、Zhengkun Yu
DOI:10.1002/adsc.201900402
日期:2019.8.21
d alkyl‐Heck‐type cross‐coupling of olefinic C−Hbonds has been a challenge in the C−H activation area. Herein, we report FeCl3‐promoted efficient direct C−Hcyanoalkylation of internal alkenes, that is, ketene dithioacetals, with cycloketone oxime esters via radical C−C bond cleavage under the redox‐neutral conditions. With CuCl2 as the catalyst under a dioxygen atmosphere direct C−H cyanoalkoxylation
These precursors are easily accessible from aryl methyl ketones. Various functional groups like alkyl, aryl, nitrile, amine, aroyl and thiomethyl can be directly installed to the benzene ring. The one-pot approach for the construction of thiomethylated-benzene nucleus was also developed. The structure of the synthesized compound was confirmed by X-ray crystallography.
Alternative Palladium-Catalyzed Vinylic C−H Difluoroalkylation of Ketene Dithioacetals Using Bromodifluoroacetate Derivatives
作者:Shuangquan Tian、Xiaoning Song、Dongsheng Zhu、Mang Wang
DOI:10.1002/adsc.201701554
日期:2018.4.3
A palladium‐catalyzedcross‐coupling of α‐oxo ketene dithioacetals and bromodifluoroacetate derivatives has been developed for the synthesis of a class of CF2‐containing tetra‐substituted olefins, which has potential to extend to drug design and material application. The process is proposed to involve two single electron transfer processes accompanied by an alternative loop from palladium(0) to palladium(I)
Efficient trifluoromethylation of C(sp<sup>2</sup>)–H functionalized α-oxoketene dithioacetals: a route to the regioselective synthesis of functionalized trifluoromethylated pyrazoles
作者:N. Sharma、N. Kumari、T. S. Chundawat、S. Kumar、S. Bhagat
DOI:10.1039/c7ra01130j
日期:——
An operationally simple approach for the regioselective construction of diversely substituted trifluoromethylated pyrazoles via nucleophilic trifluoromethylation of iodo-substituted α-oxoketene dithioacetals is described. X-ray crystallographic studies confirmed the trifluoromethylation as well as formation of a regioselective cyclized product. Furthermore, trifluoromethylated pyrazoles bearing thiomethyl
BF3·OEt2-mediated alkenylation of pyrroles with α-oxo ketene dithioacetals
作者:Xiaoge Yang、Kaikai Wu、Zhengkun Yu
DOI:10.1016/j.tetlet.2015.05.102
日期:2015.7
BF3·OEt2-mediated alkenylation of pyrroles with α-oxo ketene dithioacetals was efficiently realized, affording mono- and disubstituted ketene pyrrolyl acetals. In the cases of using N-unprotected pyrrole, the reactions gave ketene bipyrrolyl acetals as well as N,O-chelated BF2 complexes. Diverse C–S transformations were achieved for the monosubstituted products, yielding N-heterocycles or multisubstituted