O-Diphenylphosphinobenzoic acid

A further reaction of [Ir(cod)Cl]2 with 3,4-dimethylphosphaferrocene, (355), yields the trigonal-bipyramidal complex [Ir(355)3(cod)]BF4, (356). 79 (356) reacts with H2 under pressure to give [Ir(355)4H2]+. Reaction of Ir(cod)Cl]2 with o-diphenylphosphinobenzoic acid ethyl ester (dpes), (357), yields [IrCl(cod)(dpes)], where dpes is acting as a monodentate P-donor-atom ligand.580 When dpes is reacted with [Ir(cod)2]BF4, then the structurally determined... 

The oligomerization reaction is believed to involve a nickel hydride, which is generated in situ from nickel(O), triphenylphosphine, and the phenyl ester of o-diphenylphosphinobenzoic acid. The trimerization of ethylene to 1-hexene is described in Figure 14. 

The oligomerization reaction is carried out in a polar solvent in which the nickel catalyst is dissolved but the nonpolar products, the a-olefins, are nearly insoluble. Preferred solvents are alkanediols, especially 1,4-butanediol. This was one of the first examples of a biphasic liquid/liquid system to be used in catalysis and is one of the key features of the process. The nickel catalyst is prepared in situ from a nickel salt, e.g., nickel chloride, and a chelating PnO ligand like o-diphenylphosphinobenzoic acid (Structure 1) by reduction with sodium boro-hydride [30, 39]. Suitable ligands are the general type of diorganophosphino acid derivatives (2). 

Two stereogenic centers are established on allylation of a-substituted P-keto esters and cyanoacetic esters with secondary cinnamyl acetates. The reaction is directed toward a regio-selective and diastereoselective pathway when o-diphenylphosphinobenzoic acid is used as a hgand. ... 

Allylation. Linear products are obtained from the Ru-catalyzed allylation of active methylene compounds (deprotonated by LiHMDS) with either primary or secondary allylic acetates. A suitable ligand for the Ru metal is o-diphenylphosphinobenzoic acid. 

In the case of the phenyl ligand we need to improve the synthesis of the phosphine component, o-diphenylphosphinobenzoic acid, develop a scalable coupling method, and... 

This reaction has been nsed in the preparation of a series of pharmacologically active amines [ 104] and diamines [105]. A stereoselective version of this reaction by nsing the directing group o-diphenylphosphinobenzoic acid has been reported [ 106] (Figure 27). 

The entire process is schematized on Figure 4. In the first step, ethylene is oligomerized in the presence of a homogeneous nickel phosphine catalyst. This catalyst is a nickel hydride generated by reduction of a nickel salt in the presence of a chelating ligand such as diphenylphosphinobenzoic acid or by reaction of nickel(O) with a phosphorus ylide. 

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