Arylation of Hydrocarbyl Ligands Formed from n ‐Alkanes through C–H Bond Activation of Benzene Using a Triruthenium Cluster

Triruthenium complex 2 containing a perpendicularly coordinated 1‐pentyne ligand, which is one of the key intermediates of the reaction of triruthenium pentahydrido complex 1 with n ‐pentane, reacts with benzene to yield μ 3 ‐benzyne–μ 3 ‐pentylidyne complex 5 by C–H bond activation. β‐H elimination form the μ 3 ‐penytylidyne ligand occurred upon heating to yield μ 3 ‐pentenylidene complex 6 , which was followed by the formation of closo ‐ruthenacyclopentadiene complex 8 by the connection of the two hydrocarbyl moieties placed on each face of the triruthenium plane with partial metal–metal bond breaking. Treatment of 8 with pressurized hydrogen resulted in exclusive liberation of n ‐pentylbenzene, which is difficult to synthesize by conventional Friedel–Crafts alkylation. These sequential transformations correspond to the formation of linear alkylbenzene by the reaction of pentane with benzene on a trimetallic plane. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)