1616860-33-3Relevant academic research and scientific papers
Synthesis of new N-substituted chiral phosphine-phosphoramidite ligands and their application in asymmetric hydrogenations and allylic alkylations
Balogh, Szabolcs,Farkas, Gergely,Tóth, Imre,Bakos, József
, p. 666 - 673 (2015)
Phosphine-phosphoramidite ligands containing a 2,4-pentanediyl backbone, BINOL moieties, and Me, Bn or Ph substituent on the nitrogen were synthesized and fully characterized. The electronic effect of the N-substituents was examined by 31P NMR of their corresponding seleno-phosphate-amide and phosphine-selenide derivatives. The new ligands together with their earlier reported derivatives were tested in the palladium catalyzed asymmetric allylic alkylation of rac-(E)-1,3-diphenylallyl acetate. Remarkably high activity (up to 1780 h-1 turnover frequency) and first order kinetics were observed by facilitating nucleophile formation. The substituent at the nitrogen and the configuration of chiral moieties had a high impact on the enantioselectivity. The new ligands were also tested in the rhodium-catalyzed asymmetric hydrogenation of methyl (Z)-α-acetamidocinnammate, dimethyl itaconate (up to 99.9% ee's) and methyl 2-acetamidoacrylate (up to 99.5% ee).
Aminoalkyl-phosphine (P,N) ligands with pentane-2,4-diyl backbone in asymmetric allylic substitution reactions
Császár, Zsófia,Imre, Patrik,Balogh, Szabolcs,Bényei, Attila,Farkas, Gergely,Bakos, József
, p. 2069 - 2077 (2017/10/30)
Abstract: The asymmetric allylic substitution reaction of rac-1,3-diaryl-2-propenyl acetates with several C- and N-nucleophiles catalyzed by the palladium-complexes of eleven structurally analogous aminoalkyl-phosphines (P,N) with pentane-2,4-diyl backbone is reported. The role of the N-substituents and the influence of the ligand/palladium molar ratio on the activity and enantioselectivity of the catalytic system are studied. The solvent and the temperature dependence of the catalytic reaction were also assessed yielding enantioselectivities up to 95% in alkylation and 90% in amination processes under optimized reaction conditions.
Synthesis of hemilabile P,N-ligands with a pentane-2,4-diyl backbone
Farkas, Gergely,Császár, Zsófia,Balogh, Szabolcs,Tóth, Imre,Bakos, József
supporting information, p. 4120 - 4122 (2014/07/22)
A general and convenient two-step synthetic method has been developed for the preparation of a novel class of aminoalkyl-phosphine type compounds, which involves nucleophilic ring-opening of cyclic sulfate esters. The ring-opening step was performed using several different aliphatic and aromatic amines to produce aminoalkyl sulfates that were reacted with LiPPh2 to give the corresponding P,N-ligands. The desymmetrization procedure affords an easy route to synthesize enantiomerically pure pentane-2,4-diyl based P,N-ligands with a highly tunable structure. The ligands derived from primary amines have a stereogenic N-atom that can be useful in asymmetric catalytic syntheses.
