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.
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
S-functionalized internal olefins, that is, α-oxo ketene dithioacetals, was efficiently achieved with alcohols as the alkoxylating agents, (diacetoxyiodo)benzene (PhI(OAc)2) as the oxidant, and benzoquinone (BQ) as the co-oxidant. The alkoxylated olefins were thus constructed and applied for the synthesis of alkoxylated N-heterocycles. Polarization of the olefinic carbon-carbon doublebond by the electron-donating
Copper(II)-Mediated Intramolecular Cyclopropanation of Ketene <i>N</i>,<i>X</i>-Acetals (X = S, O, N) under Mild Conditions
作者:Fei Huang、Ping Wu、Zhengkun Yu
DOI:10.1021/acs.joc.0c00093
日期:2020.3.20
CuBr2-mediated intramolecular oxidative cyclopropanation of α-oxo ketene N,S-acetals was efficiently achieved to afford 2-thioalkyl-3-azabicyclo-[3.1.0]hexenes under mild conditions. 2-Oxyalkyl- and 2-aminoallyl-3-azabicyclo-[3.1.0]hexenes were also obtained from the corresponding α-oxo ketene N,O- and N,N-acetals. Further C-S bond transformations led to diverse 2-aryl-substituted 3-azabicyclo[3.1