Stoichiometric to catalytic reactivity of the aryl cycloaurated species with arylboronic acids: insight into the mechanism of gold-catalyzed oxidative C(sp)-H arylation.

Based on the well-defined five-membered aryl gold(iii) complexes, [Au(tpy)X] ( and ) and [AuBr(Ph)(tpy)] (), as well as the aryl gold(iii) complex [AuCl(Ph)(tpy)] () (tpy = 2-(-tolyl)pyridine) as reliable models, we present a detailed study of the mechanism for gold(iii)-catalyzed oxidative cross-coupling reactions between cycloaurable arenes and arylboronic acids. Here we report the direct evidence for a mechanistic proposal including arene C-H activation, transmetallation and biaryl reductive elimination. The chelation-assisted C-H activation strategy has been used for the development of the gold(iii)-catalyzed C-H bond arylation of arenes with aryl reagents to forge extended π-conjugated systems.