Synthesis of N-aryl imidazoles catalyzed by copper nanoparticles on nanosized silica coated maghemite

FABIANA NADOR; MARÍA A. VOLPE; FRANCISCO ALONSO; GABRIEL RADIVOY

TETRAHEDRON

PERGAMON-ELSEVIER SCIENCE LTD

Lugar: Amsterdam; Año: 2014 vol. 70 p. 6082 - 6087

0040-4020

A magnetically recoverable catalyst consisting of copper nanoparticles (CuNPs) on nanosized silicacoated maghemite is presented. The catalyst has been prepared under mild conditions by mixing the magnetic support with a freshly prepared suspension of CuNPs obtained by fast reduction of anhydrous CuCl2 with lithium sand and a catalytic amount of DTBB (4,40-di-tert-butylbiphenyl) as electron carrier. This copper-based catalyst has shown to be very efficient in the N-(hetero)arylation of imidazole using (hetero)aryl bromides and iodides as arylating agents under ligand-free conditions. The catalyst is easily recovered by means of an external magnet and can be reutilized in three N-arylation cycles without apparent loss of catalytic activity.