Substituent effects in the ruthenium catalyzed hydrosilylation of para-substituted phenylacetylenes

Paris, Shadrick I.M.; Lemke, Frederick R.

doi:10.1016/j.inoche.2005.02.003

Cited by 18 publications

(4 citation statements)

References 3 publications

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“…The metal complexes containing large bite angle ligands such as xantphos, [9, 9-dimethyl-4, 5-bis (diphenylphosphino) xanthene], and others with a relatively similar moiety exhibit noticeable coordination chemistry along with catalytic activity [8][9][10]. Over the last decades, the ruthenium catalyzed reactions directed to organic synthesis have got much attention and a large number of highly efficient synthetic approaches are well documented in literature [11][12][13][14][15][16][17]. Recently, extensive research has been assigned to the improvement of rutheniumcatalyzed hydrogenation of unsaturated polar bonds such as aldehydes and ketones [18][19][20].…”

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confidence: 99%

Ru(II) xantphos complex as an efficient catalyst in transfer hydrogenation of carbonyl compounds

Kharat¹,

Bakhoda²,

Jahromi³

2011

Inorganic Chemistry Communications

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confidence: 99%

Ru(II) xantphos complex as an efficient catalyst in transfer hydrogenation of carbonyl compounds

Kharat¹,

Bakhoda²,

Jahromi³

2011

Inorganic Chemistry Communications

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“…The reactivity trend observed with catalyst 1 contrasts with that of some ruthenium catalysts in which electron-withdrawing substituents increased phenylacetylene reactivity toward hydrosilylation . On the other hand, no major effects arising from the electronic effects of para substitution of phenylacetylenes, neither in the activity nor in the selectivity, were found in catalytic systems based on Rh III and Ir III catalyst precursors featuring a functionalized bis-N-heterocyclic carbene ligand. , …”

Section: Resultsmentioning

confidence: 75%

Hydrosilylation of Terminal Alkynes Catalyzed by a ONO-Pincer Iridium(III) Hydride Compound: Mechanistic Insights into the Hydrosilylation and Dehydrogenative Silylation Catalysis

et al. 2016

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The catalytic activity in the hydrosilylation of terminal alkynes by the unsaturated hydrido iridium(III) compound [IrH(κ3-hqca)(coe)] (1), which contains the rigid asymmetrical dianionic ONO pincer ligand 8-oxidoquinoline-2-carboxylate, has been studied. A range of aliphatic and aromatic 1-alkynes has been efficiently reduced using various hydrosilanes. Hydrosilylation of the linear 1-alkynes hex-1-yne and oct-1-yne gives a good selectivity toward the β-(Z)-vinylsilane product, while for the bulkier t-Bu-CCH a reverse selectivity toward the β-(E)-vinylsilane and significant amounts of alkene, from a competitive dehydrogenative silylation, has been observed. Compound 1, unreactive toward silanes, reacts with a range of terminal alkynes RCCH, affording the unsaturated η1-alkenyl complexes [Ir(κ3-hqca)(E-CHCHR)(coe)] in good yield. These species are able to coordinate monodentate neutral ligands such as PPh3 and pyridine, or CO in a reversible way, to yield octahedral derivatives. Further mechanistic aspects of the hydrosilylation process have been studied by DFT calculations. The catalytic cycle passes through Ir(III) species with an iridacyclopropene (η2-vinylsilane) complex as the key intermediate. It has been found that this species may lead both to the dehydrogenative silylation products, via a β-elimination process, and to a hydrosilylation cycle. The β-elimination path has a higher activation energy than hydrosilylation. On the other hand, the selectivity to the vinylsilane hydrosilylation products can be accounted for by the different activation energies involved in the attack of a silane molecule at two different faces of the iridacyclopropene ring to give η1-vinylsilane complexes with either an E or Z configuration. Finally, proton transfer from a η2-silane to a η1-vinylsilane ligand results in the formation of the corresponding β-(Z)- and β-(E)-vinylsilane isomers, respectively.

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“…Changing the alkyl groups, a slightly better transformation was recorded with 4-ethyl phenylacetylene (Table 2, entry 1f). The inert and difficult-to-activate molecules such as 4-methoxy and 2-methoxy substituted phenylacetylene showed efficient transformations of 87% and 84% for the desired product (Table 2, entries 1g and 1h) [64][65][66]. The halides, 4-fluoro, 4-chloro, and 4-bromophenylacetylene also reacted and showed 86, 80, and 74% transformations of the respective keto products (Table 2, entries 1i-1k).…”

Section: Resultsmentioning

confidence: 99%

Facile Photochemical/Thermal Assisted Hydration of Alkynes Catalysed under Aqueous Media by a Chalcogen Stabilized, Robust, Economical, and Reusable Fe3Se2(CO)9 Cluster

et al. 2023

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In this report, the catalytic potential of chalcogen-stabilized iron carbonyl clusters [Fe3E2(CO)9 (E = S, Se, Te)] for the photolytic hydration of alkynes has been explored. The iron chalcogenide clusters bring excellent transformations of terminal and internal alkynes to their respective keto products in just 25 min photolysis at −5 °C in inert free and aqueous conditions. After the completion of the reaction, the product can be extracted from organic solvent, and due to the lower solubility of the catalyst in water, it can also be isolated and further reused several times prior to any activation. The catalyst was also found to be active in thermal conditions and bring about the desired transformations with average to good catalytic efficiency. Moreover, during the thermal reaction, the catalyst decomposed and formed the nanoparticles of iron selenides, which worked as a single-source precursor for FeSe nanomaterials. The presented photolysis methodology was found to be most feasible, economical, instantly produce the desired product, and work for a wide range of internal and terminal alkynes; hence, all these features made this method superior to the other reported ones. This report also serves as the first catalytic report of chalcogen-stabilized iron carbonyl clusters for alkyne hydrations.

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Substituent effects in the ruthenium catalyzed hydrosilylation of para-substituted phenylacetylenes

Cited by 18 publications

References 3 publications

Ru(II) xantphos complex as an efficient catalyst in transfer hydrogenation of carbonyl compounds

Ru(II) xantphos complex as an efficient catalyst in transfer hydrogenation of carbonyl compounds

Hydrosilylation of Terminal Alkynes Catalyzed by a ONO-Pincer Iridium(III) Hydride Compound: Mechanistic Insights into the Hydrosilylation and Dehydrogenative Silylation Catalysis

Facile Photochemical/Thermal Assisted Hydration of Alkynes Catalysed under Aqueous Media by a Chalcogen Stabilized, Robust, Economical, and Reusable Fe3Se2(CO)9 Cluster

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