Reversible P–C bond formation for saturated α-aminophosphine ligands in solution: stabilization by coordination to Cu(I)

Amino‐phosphanes in RhI‐Catalyzed Hydroformylation: New Mechanistic Insights Using D2O as Deuterium‐Labeling Agent

“…1 3 }], were prepared according to the literature. [11,15,44,45] The preparation of the optically pure version of the latter ligand, (S,S)-1, has been previously reported [11] The synthesis of complex [RhCl(COD)(α-P,N)] 1 with α-P,N=Ph 2 PCH(o-C 6 H 4 Cl[Cr(CO) 3 ])NHPh has previously been described. [17] The (R)-2-phenylpropanal was prepared by an oxidation reaction using the Dess-Martin reagent [46] from commercially available (R)-2-phenyl-1-propanol (Aldrich) according to a previously described procedure [47] (ee = 93 % by use of the NMR chiral shift reagent [Eu(hfc) 3 ], according to the literature [48] ).…”

“…For example, when a pyridinylphosphane is only P-coordinated in a Pd II complex, the dangling amine function acts then as a "proton messenger" in alkyne methoxycarbonylation catalysis, [2] whereas a selective P,N chelation of a chiral phosphanediamine induces an effective chiral field in the rhodium complex leading to a higher selectivity in asymmetric hydrogenation of acrylic acid. [7] In our laboratory, we have developed different access ways to chiral α- [11] or β-P,N [12,13] and mixed α,β-and β,γ-P,P,N [14] ligands and their coordination properties have been explored in copper(), [15] palladium(), [13,16] and rhodium() complexes [14,17,18] Recently, we have examined the co- and PhCD(CH 2 D)CHO (α,β-D 2 ) were also produced. This result suggests a reversible deprotonation assisted by an intramolecular H-bonding interaction between the dangling ammonium function and the carbonyl moiety.…”

Amino‐phosphanes in RhI‐Catalyzed Hydroformylation: Hemilabile Behavior of P,N Ligands under High CO Pressure and Catalytic Properties

“…The coordinated 1,5-COD (1,5-cyclooctadiene) C and H nuclei are labeled from 1 to 8, C 1 and C 2 being trans to P. ) (γ-P,N-1), and Ph 2 P(o-C 6 H 4 -CH 2 NHPh) (γ-P,N-2) were prepared according to literature. [13,14,17,[41][42][43][44] The synthesis of complex [RhCl(COD)(α-P,N)] 1 with α-P,N=Ph 2 PCH(o-C 6 H 4 Cl[Cr(CO) 3 ])NHPh has previously been described. [18] …”

“…[13][14][15][16] Particularly, we have reported that β-P,N ligands adopt a chelating mode whereas α-P,N ligands are only P-coordinated in Cu I or in Rh I complexes. [17,18] Separate work has shown that β-P,N ligands in Rh I complexes can adopt a monodentate κ 1-P- [19] or a κ 2 -P,N-coordination mode. [15,20] Nevertheless, no direct evidence for a hemilabile character has been reported so far for β-P,N ligands in Rh I complexes.…”

Phosphine- and thiophosphorane-amine ligands: Lithiation and coordination to Rh(I)

“…Interestingly, Poli and co-workers [18] have shown some years ago that a-aminodiphenylphosphine ligands or their anionic species set up a solution equilibrium with Ph 2 PH or Ph 2 PLi and the corresponding imine. They demonstrated that the reversible P-C bond break can be suppressed or at least reduced by decreasing the electron density at the nitrogen and central carbon atoms by introducing electron-withdrawing substituents at these positions or by coordination to Cu(I) through the P atom.…”