The chiral Pt catalyst precursor Pt((R,R)-Me-Duphos)(Ph)(Cl) mediated alkylation of racemic secondary phosphines PHR(R') with benzyl halides in the presence of base to give enantioenriched tertiary phosphines PR(R')(CH2Ar). Similar reactions of bis(secondary) phosphines yielded chiral diphosphines in up to 93% ee and with good rac/meso diastereoselection.

Treatment of Pt halide precursors with the secondary phosphine PHMe(Is) in the presence of the base NaOSiMe3 gave the terminal phosphido complexes Pt(Duphos)(Ph)(PMeIs) (Is = 2,4,6-(i-Pr)3C6H2, Duphos = (R,R)-Me-Duphos (1), (R,R)-i-Pr-Duphos (2)), Pt((R,R)-Me-Duphos)(X)(PMeIs) (X = I (3), Cl (4)), and Pt((R,R)-Me-Duphos)(PMeIs)2 (5). Low-barrier pyramidal inversion in the phosphido complexes was investigated by 31P NMR spectroscopy. Protonation of 1−5 with HBF4 gave the secondary phosphine complexes [Pt(Duphos)(Ph)(PHMeIs)][BF4] (Duphos = (R,R)-Me-Duphos (6), (R,R)-i-Pr-Duphos) (7)), [Pt((R,R)-Me-Duphos)(X)(PHMeIs)][BF4] (X = I (8), Cl (9)), and [Pt((R,R)-Me-Duphos)(PHMeIs)2][BF4]2 (10); cations 6, 9, and 10 were prepared independently from Pt chloride precursors using Ag(I) salts and PHMe(Is) and then deprotonated to yield phosphido complexes 1−5. Oxidation of the phosphido ligands in 4 and 5 with H2O2 gave Pt((R,R)-Me-Duphos)(Cl)(P(O)MeIs) (11) and Pt((R,R)-Me-Duphos)(P(O)MeIs)2 (12), respectively. Complexes 1−6, 9, and 11 were structurally characterized by X-ray crystallography; structural and 31P NMR results suggest the trans influence order P(O)MeIs > PMeIs > PHMe(Is). Reaction of 1 with [Pd(allyl)Cl]2, followed by treatment with dppe, gave Pt((R,R)-Me-Duphos)(Ph)(Cl), PMeIs(allyl) (13), and Pd(dppe)2. Treatment of 1 with Pd(P(o-Tol)3)2 gave an equilibrium mixture containing the two-coordinate palladium complex Pd(P(o-Tol)3)(μ-PMeIs)Pt((R,R)-Me-Duphos)(Ph) (14), Pd(P(o-Tol)3)2, P(o-Tol)3, and 1.

The chiral Pd(0) trans-stilbene complexes Pd(diphos*)(trans-stilbene) (diphos* = (R,R)-Me-Duphos, (R,R)-Et-Duphos, (R,R)-i-Pr-Duphos, (R,R)-Me-BPE, (S,S)-Me-FerroLANE, (S,S)-Me-DuXantphos, (S,S)-Et-FerroTANE, (R,S)-CyPF-t-Bu, (R,S)-PPF-t-Bu, (R,S)-BoPhoz) and Ni((R,R)-Me-Duphos)(trans-stilbene) were prepared by NaBH(OMe)3 reduction of the corresponding M(diphos*)Cl2 compounds in the presence of trans-stilbene. The rate of oxidative addition of phenyl iodide to the stilbene complexes, which gave Pd(diphos*)(Ph)(I), depended on the ligand (larger for increased ligand bite angles and reduced steric bulk) and was markedly faster than oxidative addition to mixtures of Pd(dba)2 and diphos*. The complexes Pd(diphos*)(Ph)(I) were prepared independently by treatment of PdL2(Ph)(I) (L2 = TMEDA, (PPh3)2) with diphos*. Oxidative addition of PhI to the complexes M((R,R)-Me-Duphos)(trans-stilbene) occurred in the rate order Pd > Ni ≫ Pt. The complexes Pd(diphos*)Cl2, Pd(diphos*)(trans-stilbene), and Pd(diphos*)(Ph)(I), as well as some analogous Ni compounds, were structurally characterized by X-ray crystallography.