A new homogeneous platinum containing catalyst for the hydrolysis of nitriles

Synthetic Applications of the Parkins Nitrile Hydration Catalyst [PtH{(PMe2O)2H}(PMe2OH)]: A Review

“…The use of transition metal complexes (mainly of as catalysts under neutral and mild conditions has allowed researchers to overcome these traditional barriers, and a large number of selective catalysts for the nitrile hydration process have seen the light during the last two decades [9][10][11][12][13][14][15]. Among them, the commercially available hydride-platinum(II) complex [PtH{(PMe2O)2H}(PMe2OH)] (1), first described by Ghaffar and Parkins in 1995 [16,17], has achieved great success among organic chemists because of its outstanding activity and selectivity and its exquisite compatibility with other functional groups ( Figure 1). As a matter of fact, this platinum complex has found applications in the synthesis of a huge number of natural products and biologically active molecules of elaborate structure, making it the most widely used catalyst to date for the hydration of C≡N bonds.…”

“…The reaction proceeds at room temperature, and the complex precipitates directly in the medium, thus making its isolation easy by simple filtration (isolated yields are usually in the range 75%-80%) [16][17][18][19]. In their first studies, Parkins and Ghaffar demonstrated the ability of 1 to selectively hydrate different model nitrile substrates, such as benzonitrile, acetonitrile, acrylonitrile, or 3-cyanopyridine, employing water, aqueous ethanol, or aqueous THF as the reaction medium at 70-90 °C [16][17][18]. The remarkable activity of [PtH{(PMe2O)2H}(PMe2OH)] (1) was readily evidenced in these seminal works, with reported turnover frequencies exceeding 1400 h −1 and turnover numbers of up to 77,000.…”

“…Further evidence of the synthetic potential of complex [PtH{(PMe2O)2H}(PMe2OH)] (1) was given by de Vries and co-workers, who reported excellent yields and chemoselectivities in the hydration of a variety of sterically hindered tertiary nitriles and nitriles containing acid-or base-sensitive functional groups (some representative examples are shown in Figure 2) [21]. Concerning its mechanism of action, Ghaffar and Parkins proposed that in aqueous medium, protonation of the hydride ligand of 1 by water readily takes place, generating a vacant coordination site on the metal for substrate binding, with concomitant dihydrogen extrusion (Scheme 2) [16][17][18]. [22], and its congeners are considered to be important lead molecules for the development of new drugs for Mycobacterium tuberculosis infections [23].…”

Application of Monodentate Secondary Phosphine Oxides, a New Class of Chiral Ligands, in Ir(I)-Catalyzed Asymmetric Imine Hydrogenation

“…They are air and moisture stable. Nonchiral or racemic SPOs have been used as ligands in Pt-catalyzed hydroformylation, 21 in Pt-catalyzed hydrolysis 22 and amination 23 of nitriles, and in Pd-catalyzed aromatic substitution reactions. 24 Enantiopure SPOs have been obtained by classical resolution using (S)-mandelic acid 18,25 or a three-step resolution procedure developed by Chan.…”

Transition Metal-Catalyzed Asymmetric Reactions Using P-Chirogenic Diaminophosphine Oxides: DIAPHOXs

“…2) This property allows for the use of these compounds as air-and moisture-stable ligands in transition metal catalysis. [3][4][5] Several secondary phosphine oxides and their equivalent have been successfully applied to Pt-catalyzed reactions, 6,7) Pd-catalyzed aromatic substitution reactions, [8][9][10] Pd-and Ni-catalyzed cross coupling reactions, [11][12][13][14][15] Pd-catalyzed oxidative etherification of aldehydes, 16) and Ru-catalyzed C-H bond activation. 17,18) During the P(V)-P(III) equilibrium, stereochemical arrangement around the phosphorus center is retained.…”