Complexes [Cu(SPh)(2)](-), [Cu(SPh)I](-) and K[Cu(SPh)(2)(Ph)](+) were observed by in situ electrospray ionization mass spectrometry (ESI-MS) analysis of the copper(I)-catalyzed C-S coupling reaction under catalytic reaction conditions indicating that they are intermediates in the reaction. A catalytic cycle was proposed based on these observations.
