C–C bond-making by trapping of a nucleophilic carbene (from an electron-rich olefin) by a σ–π-acetylido(hexacarbonyl)di-iron complex; X-ray crystal and molecular structure of [(OC)₃FeC(⁺CNMeCH₂CH₂NMe)C(Ph)Fe(CO)₃PPh₂]

Abstract

Reaction of an electron-rich olefin [[graphic omitted]R′]2(R′= Me, Et, or CH2Ph) with the σ-π-acetylide [Fe2(CO)6(CCR)(PPh2)](R = Ph or But) yields the novel mesoionic complex [Fe2(CO)6(C2R)(PPh2){[graphic omitted]R′}]via carbene–acetylide coupling; X-ray analysis reveals that the carbene species is attached [C–C, 1·56(1)Å] to the α-carbon atom [attached to Fe(1)] of the acetylide with the β-carbon atom bonded to Fe(2).