Acrylamide, catalyzed hydrogenation

Preliminary kinetic data on the catalyzed hydrogenation of acrylamide using HRuCl(diop)2 generally show a first-order dependence on hydrogen, between a first- and a zero-order on both ruthenium and substrate, and an inverse dependence on added diop at lower substrate concentrations. These dependences are consistent with the mechanism outlined below (Reaction 4) and the corresponding rate law (Equation 5). The less than first-order dependence on ru-... 

Abstract Computational methods are an indispensible tool for the study of metal-organic reaction mechanisms. A particularly fruitful area is that of transition metal-catalyzed hydrogenations, including enantioselective versions that are extensively used at both the laboratory and the industrial scale. This review covers computational studies of rhodium-, ruthenium-, and iridium-catalyzed hydrogenation of enamides, acrylamides, carbonyls, and unactivated olefins. The evolution of the mechanistic models and the relationship of the computational studies to experimental studies are discussed. 

A preliminary investigation concerning the mechanism of the Rh-catalyzed hydrogenation of acrylamide substrates with model bisphosphine ligands has been reported [67]. Acrylamide was used as the model substrate and [Rh(PH3)2] as the model catalyst (Fig. 8). The mechanism tmder investigation consists of hydrogen coordination to a [Rh(acrylamide)(PH3)2] complex based on the four possible approaches of H2, oxidative addition to form dihydrides, and olefin insertion into the Rh-H bond to form alkyl hydride complexes. Reductive elimination was not examined because it is facile in comparison to oxidative addition and olefin insertion steps. 

F. 8 Proposed catalytic cycle Iot rhodium-catalyzed hydrogenation of acrylamide substrate with respect to the approach of H2... 

Zhao et al (70) developed a method for the synthesis of dendrimer-encapsulated metal nanoparticles based on sorbing metal ions into (modified) PAMAM dendrimers followed by a reduction. Dendrimers encapsulating copper, palladium, and platinum nanoparticles have been prepared. Hydroxyl-terminated PAMAM dendrimers were used to prepare encapsulated palladium (PAMAM generations 4, 6, and 8) and platinum (PAMAM generations 4 and 6) nanoparticles. The dendrimer-encapsulated palladium and platinum nanocomposites catalyzed the hydrogenation reaction of allyl alcohol and N-isopropyl acrylamide in water 71). 

Dihydroboronium derivatives of t-Bu-BisP with different cotmter anions were prepared, as shown in Scheme 56. The reaction of BisP with BH2Br afforded the boronium salt 175 which possessed a bromide ion. The dihydroboronium derivative of (S,S)-l,2-bis(tert-butylmethylphosphino)ethane 175 (t-Bu-BisP ) was prepared by the reaction of t-Bu-BisP 174 with catecholborane and used as chiral diphosphine ligand precursor in Rh-catalyzed asymmetric hydrogenated of methyl (Z)-acetamidocinnamate to afford the hydrogenation product in up to 94% ee. Complexes of iron(III) and P-chiral phosphine oxides 176 are catalysts for the asymmetric Diels-Alder reaction of iV-acrylamide dienophiles [106]. 

In the base catalyzed polymerization of acrylamide, the vinyl polymerization is reported by Nakayama et al. [7] to occur in addition to the hydrogen transfer polymerization process. 

CU2O could catalyze oxidative alkylarylation of acrylamides with simple alkanes to alkyl-substituted oxindoles using dicumyl peroxide (DCP) as radical initiator. Alkyl radical could be formed via hydrogen abstraction reaction with cumyloxyl radical which is generated from the homolysis of DCP. Then alkyl radical reacts with C=C bond followed by cyclization to benzene core and oxidation to give the alkyl-substituted oxindoles. Selective activation of unactivated C(sp )-H and C(sp2)-H bonds by one single step is achieved in this transformation [70] (Scheme 8.33). 

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