Alkenes as hydrogen trappers to control the regio-selective ruthenium(ii) catalyzed ortho C-H silylation of amides and anilides

A convenient and practical pathway to versatile silylated amides and anilides is described via efficient and selective ruthenium(ii) catalyzed ortho C-H silylation. Both amides and anilides were successfully silylated with good functional group tolerance and high regioselectivity. Different alkenes as the hydrogen acceptors played a crucial role in these two catalytic systems. Unexpectedly, two pathways for RuHCl(CO)(PPh3)(2)/KOAc catalyzed C-H silylation involving a 5-membered ruthenacycle with arylamides and a 6-membered ruthenacycle with arylanilides, take place depending on the nature of the alkene as the hydrogen trapper.