Chiral spiro aminophosphine ligand compound and synthesis …

Synthesis of Glutamic Acid and Highly Functionalized Pyrrolidine Derivatives by Utilizing Tunable Calcium Catalysts for Chemoselective Asymmetric 1,4-Addition and [3+2] Cycloaddition Reactions,
M.

T1 - Rhodium-catalyzed asymmetric synthesis of spirosilabifluorene derivatives

Enantioselective synthesis, also called chiral synthesis, asymmetric synthesis or stereoselective synthesis, is organic synthesis that selectively produces one or more new and desired elements of chirality. This methodology is important in the field of pharmaceuticals because the different enantiomers or diastereomers of a molecule often have different biological activity.


Chiral phosphine ligands in asymmetric synthesis. IV. …

A general, efficient, and highly diastereoselective method for the synthesis of structurally and sterically diverse -chiral phosphine oxides was developed. The method relies on sequential nucleophilic substitution on the versatile chiral phosphinyl transfer agent 1,3,2-benzoxazaphosphinine-2-oxide, which features enhanced and differentiated P–N and P–O bond reactivity toward nucleophiles. The reactivities of both bonds are fine-tuned to allow cleavage to occur even with sterically hindered nucleophiles under mild conditions.


Chiral phosphines in nucleophilic organocatalysis

T1 - Synthesis of new N-substituted chiral phosphine-phosphoramidite ligands and their application in asymmetric hydrogenations and allylic alkylations

With a chiral phosphine-catalyzed [3 + 2] ..

N2 - 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).

Substituted phosphine synthesis by …

AB - 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).

Triphenylphosphine - Organic chemistry

N2 - (Chemical Equation Presented) The first catalytic route toward the title compounds by asymmetric ring-closing metathesis is described. A remarkable reversal of enantioselectivity is observed when the achiral imido ligand of the chiral molybdenum-catalyst is changed (see scheme), thus highlighting the importance of the achiral and the chiral ligands in catalyst design.