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)(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 Bu^t) 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).