651043-05-9Relevant academic research and scientific papers
Iridium-assisted C≡C bond cleavage of 1-alkyne by water: Preparation of new alkyl derivatives
Albertin, Gabriele,Antoniutti, Stefano,Bacchi, Alessia,Pelizzi, Giancarlo,Piasente, Francesca
, p. 2881 - 2888 (2007/10/03)
Alkyl complexes IrCl2(η1-CH2Ar)(CO) (PPh3)2 (1) [Ar = Ph (a), p-tolyl (b)] were prepared by allowing the hydride mer- or fac-IrHCl2(PPh3)3 to react with terminal alkynes ArC≡CH in the presence of water. The complexes were characterized spectroscopically (IR and 1H, 31P, 13C NMR) and by the X-ray crystal structure determination of 1b. The acyl complex IrCl2{C(O)CH2 C(CH3)3}(PPh3)2 (2) was also prepared by reacting mer-IrHCl2(PPh3)3 with tert-butylacetylene HC≡CC(CH3)3 in the presence of H2O. A reaction path for the hydration of terminal alkyne in the presence of the Ir(III) complex leading to the cleavage of the C≡C bond, with the formation of the complexes 1 or 2 is also proposed. Acetylide complexes IrHCl(C≡CAr) (PPh3)3 (3), IrHCl(C≡CAr) (AsPh3)3 (4) [Ar = Ph (a), p-tolyl (b)] and IrHCl(C≡CPh){PPh(OEt)2}(PPh3)2 (5) were prepared by reacting IrHCl2L3 (L = PPh3, AsPh3) or IrHCl2 {PPh(OEt)2}(PPh3)2 with lithium acetylide. Protonation reaction with Bronsted acids of the acetylide 3 was also studied and led to unstable vinyl derivatives. The stable vinyl [IrCl{η2-CH=C(H)COOMe}L2]BPh4 (6,7) [L = PPh3 (6), AsPh3 (7)] complexes, instead, were prepared by allowing IrHCl2L3 to react first with AgCF3SO3 and then with methyl propiolate.
