Cooperative Catalytic Activation of Si−H Bonds by a Polar Ru−S Bond: Regioselective Low-Temperature C−H Silylation of Indoles under Neutral Conditions by a Friedel−Crafts Mechanism
Journal of the American Chemical Society2011Vol. 133(10), pp. 3312–3315
Citations Over TimeTop 10% of 2011 papers
Hendrik F. T. Klare, Martin Oestreich, Jun‐ichi Ito, Hisao Nishiyama, Yasuhiro Ohki, Kazuyuki Tatsumi
Abstract
Merging cooperative Si-H bond activation and electrophilic aromatic substitution paves the way for C-3-selective indole C-H functionalization under electronic and not conventional steric control. The Si-H bond is heterolytically split by the Ru-S bond of a coordinatively unsaturated cationic ruthenium(II) complex, forming a sulfur-stabilized silicon electrophile. The Wheland intermediate of the subsequent Friedel-Crafts-type process is assumed to be deprotonated by the sulfur atom, no added base required. The overall catalysis proceeds without solvent at low temperature, only liberating dihydrogen.
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