Reactivity of "ligand-free" Au: C-H and C-C activation versus π coordination

[(Me S)Au] cations, generated from (Me S)AuCl and AgSbF in dichloromethane at 0-20 °C, serve as sources of solvated Au (alongside unreactive [Au(SMe ) ] ), which reacts with the methyl-substituted arenes C Me H (n = 0-2) with C-H bond cleavage to give the sulfonium salts [C Me H CH SMe ] . There was no evidence for arene π coordination to Au or for the formation of σ-bonded Au-benzyl species. Surprisingly, the reaction of Au with CH Ar leads to C-C bond cleavage (Ar = 2,4,6-C H Me ). The reactions are highly selective for benzylic C-H and C-C bonds, whereas metalation of the arene ring is not observed. © 2011 American Chemical Society.