Palladium-catalyzed hydrophosphination

Scheme 5-9 Palladium-catalyzed hydrophosphination of aery lonitrile with a disecondary phosphine...

Scheme 34 Proposed mechanism for nickel- or palladium-catalyzed hydrophosphination via attack on a complex of an electron-rich alkene...

Examples of electrophilic addition of secondary phosphines to alkenes or alkynes were described. [114, 124, 125, 135]. Glueck [124-126] reported enantioselective tandem reaction of alkylated/arylation of primary phosphines catalyzed by platinum complex, proceeding with formation of chiral phosphaace-naphthenes. Palladium-catalyzed hydrophosphination of alkynes 219 tmder kinetic resolution conditions gave access to 1,1-disubstituted vinylphosphine boranes 220. However, despite screening several chiral ligands, temperatures, and solvents, the... 

The binuclear palladium complex [(tBu2PH)PdPtBu2]2 with oxygen gave a very efficient catalyst for the hydrogenation of a,/3-unsaturated carbonyls. 0 Glueck and co-workers have undertaken studies on aspects of platinum-catalyzed hydrophosphinations of activated olefins.71,72... 

Glueck et al. have reported the addition reaction to activated alkenes (Michael acceptors) and have carried out detailed mechanistic studied [121,122]. An important mechanistic study was also carried out for the palladium catalyzed asymmetric phosphination [123, 124]. Hydrophosphination of less activated olefins was achieved for the first time by Ni-catalyzed reaction using phosphite ligands (Scheme 8.44) [125],... 

Hydrophosphination catalyzed by a palladium(II) precursor has been reported. The P-H bonds of a protected bis(phenylphosphino)pyrrolidine added to acrylonitrile in the presence of catalytic amounts of PdCl2 and K2CO3 (Scheme 5-9). Without palladium, using KOH or K2CO3 as base gave only 30-40% yield. Similar catalytic chemistry was reported briefly for methyl acrylate [10]. 

Apart from being air sensitive, the generally stable M-P coordination renders technical difficulties in the elimination of the tertiary phosphine product in catalytic process involving transition metal ions as catalysts. However, the asymmetric hydrophosphination of aromatic enones could be catalyzed by the same organo-palladium (II) complex with high yields and stereoselectivity (Table 1). 

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