90990-47-9Relevant academic research and scientific papers
Formation of alkenyl ketone complexes and of dimeric α,β-butenolides by sequential insertion of phenylacetylene and carbon monoxide into nickel-acyl bonds. X-ray structures of Ni[C(Ph)=C(H)(COCH2SiMe3)]Cl(PMe3)2 and Ni[C(Ph)(PMe3)C(H)(COCH2CMe2Ph)]Cl(PMe 3)
Carmona, Ernesto,Gutiérrez-Puebla, Enrique,Monge, Angeles,Marín, José M.,Paneque, Margarita,Poveda, Manuel L.
, p. 967 - 975 (2008/10/08)
The insertion of PhC≡CH into the nickel-carbon bond of the acyls trans-Ni(COR)Cl(PMe3)2 is highly regio- and stereoselective and provides goods yields of trans-(Z)-Ni[C(Ph)=C(H)(COR)]Cl(PMe3)2 (R = CH3, 1a; R = CH2SiMe3, 1b; R = CH2CMe3, 1c; R = CH2C6H4-o-Me, 1d; R = CH2CMe2Ph, 1e). The nickel center in these complexes is in a five-coordinate distorted square-pyramidal environment, as demonstrated by an X-ray study carried out with the CH2SiMe3 derivative 1b. The neophyl complex 2e undergoes a reversible 1,2 trimethylphosphine shift and rearranges to the nickelacyclopropane complex Ni[C(Ph)-(PMe3)C(H) (COCH2CMe2Ph)]Cl(PMe3) (2) whose structure has also been determined by X-ray crystallography. Complex 1b is monoclinic of space group P21/n, while 2 is orthorhombic of space group Pbca. 1b has unit cell parameters a = 12.532 (8) ?, b = 14.099 (1) ?, b = 14.36 (1) ?, β= 98.51 (6)°, and D(calcd) = 1.23 g cm-3 for Z = 4. Corresponding values for 2 are a = 20.638 (5) ?, b = 20.09 (1) ?, c = 12.913 (5) ?, and D(calcd) = 1.26 g cm-3 for Z = 8. The keto vinyl complexes 1 react smoothly with CO (20°C, 1 atm) with formation of dimers of γ-but-2-enolactone, 3, in good yields. Formation of these dimeric α,β-butenolides can be achieved in a one-pot synthesis, starting from the alkyls NiCl(R)(PMe3)2, by successive insertion of CO, PhC≡CH, and CO.
Alkyne insertion reactions in nickel acyl complexes. Occurrence of a 1,2-trimethylphosphine shift and the X-ray structures of Ni[C(Ph)=C(H)(COCH2SiMe3)]Cl(PMe3)2 and Ni[C(Ph)(PMe3)C(H)(COCH2
Carmona, Ernesto,Gutiérrez-Puebla, Enrique,Monge, Angeles,Marín, José M.,Paneque, Margarita,Poveda, Manuel L.
, p. 1438 - 1440 (2008/10/08)
The facile formation of Ni[C(Ph)=C(H)(COR)] Cl(PMe3)2 complexes (R = CH3 (1a), CH2SiMe3 (1b), CH2CMe3 (1c), and CH2CMe2Ph (1d)) by insertion of PhC≡CH into
