Acrylonitrile complexes with platinum

Examples of the insertions of alkenes or alk5mes into metal-amido bonds are also rare. Examples of the insertions of alkenes into tihe M-N bonds of isolated amido complexes include the reaction of a rhodium anilide complex with alkenes to form imines witii kinetic behavior that is consistent with migratory insertion,and the formal insertion of the strongly electrophilic acrylonitrile into a platinum anilide. Additional examples include reactions of a lanthanide-amido complex generated in situ, a catalytic carboamination process in which the stereochemistry implies insertions of olefins into amides, and a catalytic hydroamination that appears to occur through an aminoalkyl complex generated by S3m addition of the iridium and amido groups across the C=C bond of norbomene. 

Glueck s group has reported catalytic DKR processes in which secondary phosphines were converted into the corresponding enantio-enriched tertiary phosphines by platinum-catalysed asymmetric hydrophosphination of acrylonitrile, or by platinum-catalysed asymmetric alkylation of secondary phosphines. The key intermediates were diastereomeric phosphide complexes with chiral ancillary ligands (L -Pd PRR )- Their relative rates of P-inversion and phosphorus-carbon bond formation controlled the enantioselectivity of the product formation. As shown in Scheme 2.66, the reactions allowed moderate enantioselectivities of up to 71% ee and 77% ee, respectively, to be achieved. 

The corresponding complexes with iV-coordinated acrylonitrile or 7r-coordinated ethylene 120 and 121 are prepared from the reactions of AgBp4 with a chloro(methyl)platinum complex in the presence of the olefins, respectively (Scheme... 

The mononuclear mechanism is similar to the one proposed for platinum-catalyzed hydrophosphination of formaldehyde (Scheme 5-3), but also includes a second P-C bond-forming pathway nucleophilic (Michael) attack of the phosphido ligand on coordinated acrylonitrile. The binuclear mechanism is similar, but P-C bond formation is proposed to occur by cooperative action of two Pt centers, with complexes 4 - 6 as possible intermediates [8]. 

The reaction of (dppe)PtMe(OMe) (dppe = bis(l,2-diphenylphosphino)ethane) with F2C=CF2 has been shown to give (dppe)PtMe(CF2CF20Me), providing the first example of an alkene insertion into an M-OR bond. Interestingly, the platinum alkyl-alkoxide complex does not react with ethene or pentene but similar to 4-tetrafluoro-ethylene other activated alkenes such as acrylonitrile and methylacrylate also undergo insertion reactions. It is noteworthy that the reaction does not involve nucleophilic attack on a coordinated alkene by free methoxide ion. The transformation of a M-OR bond into a M-R bond appears to be thermodynamically favourable in this instance. 

Pd complexes of polymeric diphenylphosphinyl ferrocene are effective catalysts for the hydrosilylation of styrene and 1-hexene by SiHCls. They can be recycled with no loss of activity.Nitrile groups on macroporous copolymers of acrylonitrile/divinylbenzene/ styrene are effective ligands for the immobilization of Rh(I), Pt(II), and Pd(II) complexes, which can be used as hydrosilylation catalysts, with their effectiveness closely related to the morphology of the polymer matrix. Similar transformation was also effected by platinum catalyst immobilized by mercaptan groups over polysiloxane. ... 

Platinum phosphine complexes catalyze the addition of PH 3 to acrylonitrile. The mechanism of conversion of HP(CH2CH2CN)2 to P(CH2CH2CN)3 was studied in detail and appears to involve dimeric species (Scheme 13). Complexes (15), (16) and (17) were observed by NMR. The formation of (16) is favored since, in contrast to reactions with ethylene, acrylonitrile is not displaced by phosphines. 

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