C-C σ-Bond Oxidative Addition and Hydrofunctionalization by a Macrocycle-Supported Diiron Complex
Tianchang Liu1, Ryan P Murphy1, Patrick J Carroll1
1Roy and Diana Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States.
Abstract:
This report describes the first examples of unassisted C(sp)-C(sp2) and C(sp)-C(sp3) bond oxidative addition reactions to give thermodynamically favorable products. Treatment of a diiron complex supported by a geometrically and electronically flexible macrocyclic ligand, (3PDI2)Fe2(μ-N2)(PPh3)2 ([FeN]), with stoichiometric amounts of various 4,4'-disubstituted diphenylacetylenes (ArX-C≡C-ArX; X = OMe, H, F, CF3) yielded C(sp)-C(sp2) bond oxidative addition products. When Ph-C≡C-R substrates were used as substrates (R = Me, Et, Pr, Bu), products of either C(sp)-C(sp2) or C(sp)-C(sp3) bond activation were obtained, with the less sterically encumbering alkynes exclusively undergoing C(sp)-C(sp3) bond activation. Treatment of the C-C activation species with either H2 or HBpin was found to form products of C-C σ-bond hydrofunctionalization. In both the hydrogenation and hydroboration schemes, the diiron species was observed to return to [FeN], thereby completing synthetic cycles for C-C σ-bond functionalization.
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