Silylium Ion Catalyzed C–H Arylation of Hydrocarbons
Arylation of Hydrocarbons Enabled by Organosilicon Reagents and Weakly Coordinating Anions.
16. Mai 2017 (online)
The Nelson group reports a silylium ion catalyzed arylation of C(sp2)–H and C(sp3)–H bonds. By employing 2–5 mol% of precatalyst A in the presence of a trialkylsilane initiator, various aliphatic and aromatic hydrocarbons were arylated with variously functionalized trimethylsilyl fluorobenzenes.
Previously, catalytic reactions involving highly reactive phenyl cation equivalents were limited to intramolecular transformations. The authors describe the formation of a β-silicon-stabilized phenyl cation (equivalent) II, which is proposed to subsequently undergo intermolecular insertion into the C–H bond of a hydrocarbon present in large excess. Desilylation of the resulting Wheland intermediate furnishes the product and regenerates the catalytically active species I.