Successive Activation of C–H and C–O Bonds of Vinyl Ethers by a Diphosphine and Hydrido-Bridged Diiridium Complex

Abstract

The reaction of [(Cp*Ir)2(μ-dmpm)(μ-H)][OTf] (2) [Cp* = η5-C5Me5, dmpm = bis(dimethylphosphino)methane] with 2,3-dihydrofuran gives [(Cp*IrH)2(μ-dmpm){μ-(2,3-dihydrofuranyl)}][OTf] (3) in an isolated yield of 70% via the C–H bond activation at the 5-position of 2,3-dihydrofuran. Complex 3 is slowly converted into [(Cp*Ir)2(μ-dmpm)(μ-C=C(H)CH2CH2OH)][OTf] (4) quantitatively via the proton-mediated C–O bond activation. The reaction of 2 with ethyl vinyl ether gives [(Cp*Ir)2(μ-dmpm)(μ-CH=CH2)][OTf] (5) in the isolated yield of 64% via the successive activation of C–H and C–O bonds.

Ni(0)-promoted activation of Csp2–H and Csp2–O bonds

“… 35 Recently, the Fujita group reported that [(η 5 -C 5 Me 5 Ir) 2 (μ-bis(dimethylphosphino)methane) (μ-H)][OTf] reacts with ethyl vinyl ether to give a dimeric Ir complex featuring a bridging vinyl ligand. 36 Conveniently, the vinyl complex 5 can be prepared in >93% yield via the reduction of ( acri PNP)NiCl with a magnesium powder in the presence of ethyl vinyl ether, see ESI. † This result may verify that a low-valent nickel species favours nucleophilic reaction with vinyl ether to cleave a C–O bond.…”