BINOL-derived diphosphoramidites bearing unsymmetrical 1,2-diamine link and their application in asymmetric catalysis

New P,P-bidentate diastereomeric diphosphoramidite chiral ligands with mixed stereogenic elements and a C₁ backbone symmetry have been prepared from (S_a)- and (R_a)-1,1′-binaphthyl-2,2′-diol (BINOL) and (S)-N-benzyl-1-(pyrrolidin-2-yl)methanamine and are fully characterized. The use of these ligands provides up to 84% ee in the Pd-catalyzed asymmetric allylic substitution of (E)-1,3-diphenylallyl acetate and up to 95% ee in the Rh-catalyzed asymmetric hydrogenation of α-dehydrocarboxylic acid esters. The results indicate that the catalytic performance is highly affected by the axial chirality of the binaphthyl moieties of the ligand and the nature of the solvent.     

Pd-Catalyzed asymmetric transformations involving P*-mono- and P*,N-bidentate diamidophosphites derived from (2S,3S)-N 2,3-dimethyl-N 1-phenylpentane-1,2-diamine

The synthesis of new P*-mono- and P*,N-bidentate diamidophosphites, containing 1,3,2-diazaphospholidine rings formed starting from (2S,3S)-N ²,3-dimethyl-N ¹-phenylpentane-1,2-diamine, is described. Comparison of their efficiency in the Pd-catalyzed enantioselective allylation with (E)-1,3-diphenylallyl acetate showed that up to 97% ee was reached in the reaction involving dimethyl malonate as a C-nucleophile. The Pd-catalyzed desymmetrization of N,N′-ditosyl-meso-cyclopent-4-ene-1,3-diol biscarbamate gave up to 61% ee.     

Tartaric acid-derived chiral phosphite-type P,N-ligands: behavioural features in Pd-catalyzed asymmetric transformations

A practical synthesis of new phosphoramidite, phosphite and diamidophosphite P,N-ligands derived from (R,R)-tartaric acid was carried out. A study of these chiral inducers showed them to provide up to 93% ee in the Pd-catalyzed asymmetric allylations of (E)-1,3-diphenylallyl acetate, up to 84% ee in the Pd-catalyzed asymmetric alkylation of cinnamyl acetate with ethyl 2-oxocyclohexane-1-carboxylate and up to 63% ee in the Pd-catalyzed desymmetrization of N,N′-ditosyl-meso-cyclopent-4-ene-1,3-diol biscarbamate. The effects of the structural modules, such as the nature of the phosphorus-containing ring or exocyclic substituent as well as of the nature of palladium source on the catalytic activity and enantioselectivity were investigated.     

Diastereomeric P,N-bidentate amidophosphites based on (S,S)- and (R,R)-hydrobenzoin as ligands in the Pd-catalyzed asymmetric allylation

New P,N-bidentate diastereomeric amidophosphite ligands were obtained by phosphorylation of (S)-2-[(phenylamino)methyl]pyrrolidine involving (4S,5S)- and (4R,5R)-2-chloro-4,5-diphenyl-1,3,2-dioxaphospholanes. Their efficiency in the Pd-catalyzed enantioselective allylic substitution was compared, it was found that the reaction involving (E)-1,3-diphenylallyl acetate and pyrrolidine gives up to 75% ee.     

Chiral 1,3,2-dioxaphospholane amidophosphite in the palladium-catalyzed enantioselective allylation

Phosphorylation of (S)-1,1,2-triphenylethane-1,2-diol furnishes cyclic P*-chiral amidophosphite, whose application as a ligand in the Pd-catalyzed allyl substitution in 1,3-diphenylallyl acetate provides the products ee up to 70%.     

Pd-Catalyzed asymmetric allylation involving bis(diamidophosphite) based on the salen-type chiral diamine

Russian Chemical Bulletin - New bis(diamidophosphite) ligand with stereogenic phosphorus atoms in the 1,3,2-diaza-phospholidine rings was synthesized based on (1R,2R)-[N,...     

Palladium and rhodium-catalyzed enantioselective reactions mediated by pseudodipeptide-based phosphite-type ligand

Russian Chemical Bulletin - P*-Chiral diamidophosphite ligand of a 1,3,2-diazaphopholidine series bearing the exocyclic pseudodipeptide fragment was synthesized. The possibility of its application...     

Diastereomeric bisamidophosphites based on oxalamide 1,3-diol in asymmetric metal complex catalysis

Diastereomeric P*,P*-bisdiamidophosphite ligands of the 1,3,2-diazaphospholidine series bearing an oxalamide moiety have been synthesized. A possibility of their application in palladium- and rhodium-catalyzed asymmetric transformations was demonstrated. In Pd-catalyzed sulfonylation of (E)-1,3-diphenylallyl acetate with sodium p-toluenesulfinate enantioselectivity of up to 57% ee, in alkylation with dimethyl malonate of up to 77% ee, in amination with pyrrolidine of up to 78% ee, and in alkylation of cinnamyl acetate with ethyl 2-oxocyclohexane-1-carboxylate of up to 52% ee, in Rh-catalyzed hydrogenation of (Z-methyl 2-acetamido-3-phenylacrylate of up to 88% ee was achieved. An effi ciency of diastereomeric chirality inducers was compared.