P-Phos ligands

Six-membered biheteroaromatic diphosphines ligands 3.2.1 Dipyridylphosphine ligands P-PHOS... 

The 3,3 -bipyridyl-based axially chiral diphosphine ligand (P-Phos) has found several applications in rhodium- and ruthenium-catalyzed homogeneous reactions (50). 

The ligands tested were tol-binap, dipamp, P-phos, xyl-P-phos, binam, phanephos and xyl-phanephos with the results lised in Table E Table 2 shows the effect which... 

DIMETHYLPHENYL)PHOSPHINO]-3,3 -BIPYRIDINE [(R)-Xyl-P-Phos] AS A LIGAND FOR RHODIUM-CATALYZED ASYMMETRIC HYDROGENATION OF a-DEHYDROAMINO ACIDS... 

In this class of ligands, the biphenyl backbone has been replaced with a dipyridylphosphine and called P-Phos (120). (These ligands have been licensed to Johnson Matthey.) The synthesis is shown in Scheme 12.45.147-149... 

Despite the lower catalytic activities and enantioselectivities to other axial bisphosphines, the greatest advantage of P-Phos is its stability to air. All ligands, intermediates, and catalysts have shown a remarkable tolerance to air,148 150 153 which can greatly simplify production operations that need to perform time-consuming air-exclusion procedures. 

The diamine ligands that have shown the most consistent usage are DPEN (145) and diapen (146). The best bisphosphines ligands used to date have been axial bisphosphines ligands, such as BINAP (3a), tol-BINAP (3b), xyl-BINAP (3c),23 188 xyl-PhanePhos (127b),162 163 and xyl-P-Phos (120c).153... 

Variation in electronic effects within the biaryl backbone has produced the P-Phos family of ligands, which contain a hindered dipyridinyl backbone. These ligands have demonstrated high catalytic activities and enantioselectivities with JST catalysts. 

Scheme 7 Synthesis of optically pure P-PHOS ligands.

The asymmetric hydrosilylation of simple ketones as well as unsymmetrical ketones was also achieved in extraordinary efficiency by a system derived from ligands of the P-PHOS series in combination with CuF2/PhSiH3 and provided up to 97% product ee s. The remarkable high activities, very mild reaction conditions and compatibility with of traces of moisture make this system practically viable (05PNA3570). 

The catalyst bearing BINAP (6.10and6.11) (developed by Noyori s group) or P-Phos ligands 6.70 (developed by Professor Albert Chan which is more active and selective than the... 

Ru catalysts with a P-Phos and a 1,2 - or 1,4-diamine ancillary ligand The catalyst (sulfonyl-diamine)RuCl(arene) 6.76, without the expensive phosphine ligand, and the hydrogen donor such as 2-propanol or formic acid in the presence of a base are used for the asymmetric transfer hydrogenation of ketones ". ... 

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