Hydrophosphination and Related Reactions

The reaction of P-H bonds with unsaturated substrates often proceeds without a metal catalyst [2]. In addition, add or base-catalyzed [3] as well as radical reactions [4] have been reported and extensively reviewed. Metal-catalyzed transformations like the ones described here, however, often offer improvements in rate, selectivity, 

Phosphine itself as well as primary and secondary phosphines undergo metal-catalyzed additions to olefins and formaldehyde. More than 40 years ago, some Ger- 

Although a wide variety of metals were claimed as active catalysts for formaldehyde hydrophosphination, platinum salts were preferred. Similarly, Group 10 metal salts were used to catalyze acrylonitrile hydrophosphination. Russian workers showed that Ni(II) or Co(II) salts in the presence of ammonia or amines would also catalyze the addition of phosphine to formaldehyde [6]. More recently, academic and industrial interest in these reactions was sparked by a series of papers by Pringle, who investigated late metal phosphine complexes as hydrophosphination catalysts. These and related studies are arranged below by substrate. 

The precatalysts, Pt(IV) or Pt(II) salts, were found to be reduced in a series of steps by excess P(CH20H)5 to give Pt[P(CH20H)5]4, which in aqueous solution exists in equilibrium with the five-coordinate cationic hydride [PtL4H][OH] [L = P(CH20H)3]. Since reaction mixtures are basic [rationalized by the formation of hemiacetals from P(CH20H)3 and formaldehyde], the major Pt species present during catalysis is ze- 

Pringle proposed a general mechanism for the reaction catalyzed by zerovalent Pt, 

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Hydrophosphination and related reactions (including reactions of heterocycles) 01MI41... 

Hydrophosphination and Related Reactions Mechanisms of C-P Bond Formation.67... 

Depending on the metal catalyst and the substrate, C-P bond formation in hydrophosphination and related reactions may occur by different pathways, including insertion into an M-P bond, P-C reductive elimination, and attack of a P-nucleo-phile on an electrophile. These typical mechanisms, ordered further by the electrophile, are surveyed below. 

These reactions involve the same organophosphorus substrates, but, in contrast to hydrophosphination and related reactions, the P-H group is not transferred to the electrophile. 

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