Abstract
Complexes [Cu(NPh 2 ) 2 ] - , [Cu(NPh 2 )I] - and K[Cu(phen)(NPh 2 ) (p-tolyl)] + were observed by in situ electrospray ionization mass spectrometry (ESI-MS) analysis of the copper(i)-catalyzed C-N coupling reaction under the catalytic reaction condition indicating that they are intermediates in the reaction. A catalytic cycle composed of a free radical path and a 2e oxidative addition path is proposed based on these observations. © 2011 The Royal Society of Chemistry.