935560-89-7Relevant academic research and scientific papers
Palladium(0)-catalyzed allylic aminations: kinetics and mechanism of the reaction of secondary amines with cationic [(η3-allyl)PdL 2]+ complexes
Amatore, Christian,Genin, Emilie,Jutand, Anny,Mensah, Laure
, p. 1875 - 1880 (2007)
The mechanism of the reaction of secondary amines (piperidine, morpholine) with the cationic complexes [(η3-PhCHCHCHR)PdL2] +BF4- (R = Ph, L = PPh3 or L 2 = dppb; R = H, L2 = dppb) has been investigated in DMF. The reaction, which affords the tertiary allylic amine, is irreversible when L is a monodentate ligand such as PPh3, whereas the reaction is reversible when L2 is a bidentate ligand such as dppb. In all cases, piperidine is more reactive than morpholine. The rate and equilibrium constants have been determined in DMF. These results can be combined with our previous results on the mechanism of the reversible formation of cationic [(nη3-PhCHCHCHPh)PdL2]+AcO- by reacting Pd0L2 complexes with (E)-PhCH=CHCH(Ph)OAc. Fully established catalytic cycles are now proposed for the Pd-catalyzed allylic amination of (E)-PhCH=CHCH(Ph)OAc by piperidine and morpholine. The amine and AcOz- are in competition in their reaction with the cationic complexes [(η3-PhCHCHCHPh)PdL2]+. The nucleophilic attack of the amine may be faster than the attack of AcO - and thus limited by the ionization step in which [(η3-PhCHCHCHPh)PdL2]+ is formed, this ionization step being turnover limiting for the catalytic cycle.
