direct CH arylation of (hetero)arenes. Starting from an aniline, the corresponding arenediazonium ion is generated in situ and immediately reduced by vitamin C to an aryl radical that undergoes a homolytic aromatic substitution with a (hetero)arene. Notably, neither heating nor irradiation is required. This procedure is mild, operationally simple, and constitutes a greener approach to arylation.
Radical C–H arylations of (hetero)arenes catalysed by gallic acid
作者:Marcelle D. Perretti、Diego M. Monzón、Fernando P. Crisóstomo、Víctor S. Martín、Romen Carrillo
DOI:10.1039/c5cc09911k
日期:——
Gallic acid is able to catalyse radical C-H arylations of (hetero)arenes with diazonium salts at room temperature in water-acetone. As gallic acid is present in multiple bio-wastes, this methodology unleashes an alternative method for waste reutilization.
A catalytic amount of a reduced form of polyaniline (a redox-active π-conjugated polymer) was found to induce C−H direct arylation of (hetero)arenes with arenediazonium salts prepared fromanilines with methanesulfonic acid (MeSO3H) and tert-butyl nitrite (tBuONO). The difficult part of this method is the coexistence of an oxidant and a reductant in this sequential diazotization and arylation system;