139198-75-7Relevant academic research and scientific papers
Application of Methyl Bisphosphine-Ligated Palladium Complexes for Low Pressure N-11C-Acetylation of Peptides
Andersen, Thomas L.,Nordeman, Patrik,Christoffersen, Heidi F.,Audrain, Hélène,Antoni, Gunnar,Skrydstrup, Troels
supporting information, p. 4549 - 4553 (2017/04/13)
A mild and effective method is described for 11C-labeling of peptides selectively at the N-terminal nitrogen or at internal lysine positions. The presented method relies on the use of specific biphosphine palladium–methyl complexes and their high reactivity towards amino-carbonylation of amine groups in the presence [11C]carbon monoxide. The protocol facilitates the production of native N-11C-acetylated peptides, without any structural modifications and has been applied to a selection of bioactive peptides.
Mechanistic studies of the palladium-catalyzed ring opening of oxabicyclic alkenes with dialkylzinc
Lautens,Hiebert,Renaud
, p. 6834 - 6839 (2007/10/03)
The mechanism of the palladium-catalyzed ring opening of oxabicyclic alkenes with dialkylzinc has been studied. Experiments which rule out a π-allyl mechanism were carried out. Trapping carbometalated products and synthesis and successful reaction of alkyl palladium species provided strong evidence in favor of an enantioselective carbopalladation as the key step in the mechanism. The studies also suggest that a cationic palladium species is responsible for carbopalladation of the alkene. The combination of palladium and dialkylzinc is unique in that the dialkylzinc functions both in the transmetalation to palladium and as a Lewis acid in forming the reactive cationic palladium species.
Influence of ligands and anions on the rate of carbon monoxide insertion into palladium-methyl bonds in the complexes (P-P)Pd(CH3)Cl and [(P-P)Pd(CH3)(L)]+SO3CF3- (P-P = dppe, dppp, dppb, dppf; L = CH3CN, PPh3)
Dekker, Guido P. C. M.,Elsevier, Cornelis J.,Vrieze, Kees,Van Leeuwen, Piet W. N. M.
, p. 1598 - 1603 (2008/10/08)
The preparation of the neutral complexes (P-P)Pd(CH3)Cl (P-P = 1,2-bis(diphenylphosphino)ethane (dppe), 1,3-bis(diphenylphosphino)propane (dppp), 1,4-bis(diphenylphosphino)butane (dppb), 1,1′-bis-(diphenylphosphino)ferrocene (dppf)) and the ionic complexes [(P-P)Pd(CH3)(CH3CN)]+SO3CF 3- (P-P = dppe, dppp, dppb, dppf) is described. The ionic dppb complex was formed as a mixture of monomeric and oligomeric forms, which can be attributed to the length and the flexibility of the backbone of the ligand. The rate of CO insertion into the Pd-CH3 bond in these complexes has been studied. The rate was found to decrease in the order dppb ≈ = dppp > dppf for the neutral complexes with half-life times ranging from 18 to 36 min at 235 K and 25 bar of CO. The dppe complex reacted much slower with a half-life time of 170 min at 305 K. The rate of carbonylation of the Pd-CH3 bond in the cationic complexes was at least 10 times higher than those of the analogous neutral complexes, the order being dppb ≈ dppp ≈ dppf > dppe with half-life times a half-life time of 2.5 min was measured. Carbonylation of the ionic PPh3-coordinated complex [(dppp)Pd(CH3)(PPh3)]+-SO3CF 3- was at least 2.5 times slower than that of the analogous CH3CN-coordinated cationic complex.
