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.
Cobalt-Catalyzed Monoselective ortho-C–H Ethylation of Carboxamides with Triethylaluminum
作者:Kun Xu、Zhoumei Tan、Haonan Zhang、Sheng Zhang
DOI:10.1055/s-0036-1589010
日期:2017.9
Published as part of the Special Topic Cobalt in Organic Synthesis Abstract A 1,10-phenanthroline ligated cobalt catalyst is reported for the ortho-C–H ethylation of aromatic, heteroaromatic, and alkenyl carboxamides with inexpensive triethylaluminum. This reaction represented the first example of cobalt-catalyzed monoselective direct ortho-C–H ethylation reaction with aluminum reagent as an alkyl donor