Dicumyl Peroxide as a Methylating Reagent in the Ni-Catalyzed Methylation of Ortho C–H Bonds in Aromatic Amides
作者:Teruhiko Kubo、Naoto Chatani
DOI:10.1021/acs.orglett.6b00658
日期:2016.4.1
The direct methylation of ortho C–H bonds in aromatic amides with dicumyl peroxide (DCP) using a nickel complex as the catalyst is reported. The reaction shows a high functional group tolerance and is inhibited by radical scavengers. In reactions of meta-substituted aromatic amides, the reaction proceeds in a highly selective manner at the less hindered C–H bonds.
N-Heterocyclic carbene–chromium-catalyzed alkylative cross-coupling of benzamide derivatives with aliphatic bromides
作者:Jinghua Tang、Pei Liu、Xiaoming Zeng
DOI:10.1039/c8cc05026k
日期:——
Described here is a chromium-catalyzed alkylative cross-coupling of benzamide derivatives with aliphatic electrophiles under mild conditions. This reaction was promoted by a low-cost and air-stable chromium(III) chloride salt combined with an N-heterocyclic carbene ligand and phenylmagnesium bromide as a reductant, and probably occurred with low-valent chromium involved in the catalytic cleavage of
Iron-Catalyzed <i>Ortho</i> C–H Methylation of Aromatics Bearing a Simple Carbonyl Group with Methylaluminum and Tridentate Phosphine Ligand
作者:Rui Shang、Laurean Ilies、Eiichi Nakamura
DOI:10.1021/jacs.6b06908
日期:2016.8.17
(Me2N-TP), that allows us to convert an ortho C-H bond to a C-CH3 bond in aromatics and heteroaromatics bearing simple carbonyl groups under mild oxidative conditions. The reaction is powerful enough to methylate all four ortho C-H bonds in benzophenone. The reaction tolerates a variety of functionalgroups, such as boronic ester, halide, sulfide, heterocycles, and enolizable ketones.
A unique C–H allylation has been discovered with unbiased aliphatic olefins. An intimate M–L affiliation between a high-valent cobalt catalyst and amino-quinoline derived benzamides has been found to be crucial for this unprecedented selectivity. An exemplary set of aliphatic olefins, high yields coupled with excellent regio- and stereoselectivity, and wide functional group tolerances are noteworthy
A simple triphenylphosphine-ligated cobalt catalyst is reported for the direct ortho-C-H methylation and ethylation of aromatic, heteroaromatic, alkenyl, and even aliphatic carboxamides with inexpensive organoaluminumreagents in the presence of a cheap alkyl chloride as oxidant. This reaction shows monoselectivity in contrast with previously established C-H methylation methodologies.