Carbon-carbon bond formation at diiron centres V. Synthesis of anionic vinyl-bridged diiron complexes and their reactivity toward alkynes - Yanez, R.; Ros, J.; Mathieu, R. (Elsevier)
The reaction of acetylenes with [PPh"4][HFe(CO)"4] in the presence of Fe"2(CO)"9 in THF solution leads to the formation in high yields of the complexes [PPh"4][Fe"2(CO)"6(μ-CO)(μ-CR^1CR^2H)] where R^1 = Ph and R^2 = H; R^1 = R^2 = Ph; R^1 = ^tBu and R^2 = H; R^1 = SiMe"3 and R^2 = H; R^1 = CO"2Me and R^2 = H. The complex [PPh"4][Fe"2(CO)"6(μ-CO)(μ-CHCRH)] with R = H or Ph) reacts with the alkynes R^3CCR^3 (R^3 = Ph, C(O)OMe, CF"3) in a different way from that previously observed for the alkyne with R^3 = Ph. The reaction involves insertion of the alkyne into the iron-carbon σ bond of the alkenyl bridge, to give [PPh"4][Fe"2(CO)"6(μ-CR^3CR^3CHCHR)] complexes (R = H). Depending on the R^3 group, two modes of bonding of the organic bridge have been observed, μ-η^2,η^2 (R^3 = Ph) and μ-η^3,η^1 (R^3 = CF"3). The complexes have been obtained from these reactions [PPh"4][Fe"2(CO)"6(μ-CR^3CR^3C(O)CHCH(R)] with R^3 = Ph; R = H; R^3 = CF"3 or C(O)OMe; R = Ph.
http://linkinghub.elsevier.com/retrieve/pii/0022-328X(90)85411-Q
Keywords: V