5815-61-2Relevant articles and documents
Disentangling ligand effects on metathesis catalyst activity: Experimental and computational studies of ruthenium-aminophosphine complexes
Chu, Crystal K.,Lin, Tzu-Pin,Shao, Huiling,Liberman-Martin, Allegra L.,Liu, Peng,Grubbs, Robert H.
, p. 5634 - 5643 (2018/05/03)
Second-generation ruthenium olefin metathesis catalysts bearing aminophosphine ligands were investigated with systematic variation of the ligand structure. The rates of phosphine dissociation (k1; initiation rate) and relative phosphine reassociation (k-1) were determined for two series of catalysts bearing cyclohexyl(morpholino)phosphine and cyclohexyl(piperidino)phosphine ligands. In both cases, incorporating P-N bonds into the architecture of the dissociating phosphine accelerates catalyst initiation relative to the parent [Ru]-PCy3 complex; however, this effect is muted for the tris(amino)phosphine-ligated complexes, which exhibit higher ligand binding constants in comparison to those with phosphines containing one or two cyclohexyl substituents. These results, along with X-ray crystallographic data and DFT calculations, were used to understand the influence of ligand structure on catalyst activity. Especially noteworthy is the application of phosphines containing incongruent substituents (PR1R′2); detailed analyses of factors affecting ligand dissociation, including steric effects, inductive effects, and ligand conformation, are presented. Computational studies of the reaction coordinate for ligand dissociation reveal that ligand conformational changes contribute to the rapid dissociation for the fastest-initiating catalyst of these series, which bears a cyclohexyl-bis(morpholino)phosphine ligand. Furthermore, the effect of amine incorporation was examined in the context of ring-opening metathesis polymerization, and reaction rates were found to correlate well with catalyst initiation rates. The combined experimental and computational studies presented in this report reveal important considerations for designing efficient ruthenium olefin metathesis catalysts.
Synthesis of N6,N6-dialkyladenine nucleosides using hexaalkylphosphorus triamides produced in situ
Lakshman, Mahesh K.,Choudhury, Asad,Bae, Suyeal,Rochttis, Eliezer,Pradhan, Padmanava,Kumar, Amit
experimental part, p. 152 - 159 (2009/07/05)
Reactions between secondary amines and phosphorus trichloride (PCl 3) leads to the formation of the corresponding tris(dialkylamino) phosphanes or hexaalkylphosphorus triamides [HAPTs: (R2N) 3P]. Treatment of silyl-protected 2′-deoxyinosine and acetyl-protected inosine with the HAPTs produced in situ, together with iodine (I2), leads to the formation of N6,N6- dialkyladenosine and -2′-deoxyadenosine. In some cases the stoichiometry of the amine is important, as is the use of a tertiary amine base. The effect of amine stoichiometry on the reaction between HAPT and I2 has been studied by 31P{1H} NMR spectroscopy. Wiley-VCH Verlag GmbH & Co. KGaA, 2009.
Dismutation of diamidoarylphosphites
Nifantyev, Edward E.,Rasadkina, Elena N.,Slitikov, Pavel V.,Vasyanina, Larisa K.
, p. 2465 - 2477 (2007/10/03)
Some examples of spontaneous dismutation of diamidoarylphosphites in different solvents were studied, and features of the process were revealed.
