Intermolecular C–H Silylation of Arenes and Heteroarenes with HSiEt3 under Operationally Diverse Conditions: Neat/Stoichiometric and Acceptor/Acceptorless

Efficient protocols for Rh-catalyzed intermolecular C–H silylation of unactivated arenes and heteroarenes are disclosed. The silylations are catalyzed by a Rh-complex (2 mol %) derived in situ from commercially available Rh­(nbd)2BF4 and (S,S)-i-Pr-BPE (L3) with Et3SiH in the presence of hydrogen acceptor under either neat (excess of arene) or stoichiometric conditions. The regioselectivity is determined mainly by the steric bulk of the substituents and by the electronic effect as an ancillary factor. In addition, our preliminary result shows that the current protocol catalyzes the silylation of arenes in the absence of hydrogen acceptors.