Highly efficient Kharasch addition catalysed by RuCl(Cp*)(PPh3)2

Simal, François; Wlodarczak, Lise; Demonceau, Albert; Noels, Alfred F.

doi:10.1016/s0040-4039(00)01048-0

Cited by 67 publications

(38 citation statements)

References 11 publications

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“…This issue has been previously reviewed by Demonceau and Noels. [24] In that contribution, ruthenium-based catalysts were classified into three main families: Grubbs-type complexes, [25] half-sandwich ruthenium complexes, [26] and ruthenium complexes bearing anionic carborane-phosphine and dicarbollide ligands (Figure 3). [27] The development of new ruthenium complexes as well as new applications for ATRA reactions has had a great impact in this field over the last few years.…”

Section: Ruthenium-based Catalystmentioning

confidence: 99%

Atom Transfer Radical Reactions as a Tool for Olefin Functionalization – On the Way to Practical Applications

2011

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Transition‐metal‐catalyzed atom transfer radical reactions of halogenated compounds with olefins constitute a versatile tool in organic synthesis within the area of C–C bond forming transformations. The inter‐ or intramolecular versions, atom transfer radical addition (ATRA) or cyclization (ATRC), respectively, lead to the atom‐economic, useful synthesis of compounds that can be further functionalized. This contribution summarizes the recent developments in this area in terms of catalyst design as well as the applicability of this methodology in sequential, domino, or tandem reactions.

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Section: Ruthenium-based Catalystmentioning

confidence: 99%

Atom Transfer Radical Reactions as a Tool for Olefin Functionalization – On the Way to Practical Applications

2011

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“…[3][4][5][6][7][8][9][10][11][12][13][14] Well-defined ruthenium benzylidene complexes, commonly used as olefin metathesis catalysts, have also been reported to catalyze ATRA and ATRP. 9,[15][16][17][18][19] The ability of ruthenium benzylidene complexes to promote two reactions with such markedly different mechanisms has been utilized in various tandem reactions in which olefin metathesis and ATR reactions take place in one pot.…”

Section: Introductionmentioning

confidence: 99%

In Situ Catalyst Modification in Atom Transfer Radical Reactions with Ruthenium Benzylidene Complexes

et al. 2016

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Ruthenium benzylidene complexes are well known as olefin metathesis catalysts. Several reports have demonstrated the ability of these catalysts to also facilitate atom transfer radical (ATR) reactions, such as atom transfer radical addition (ATRA) and atom transfer radical polymerization (ATRP). However, while the mechanism of olefin metathesis with ruthenium benzylidenes has been well-studied, the mechanism by which ruthenium benzylidenes promote ATR reactions remains unknown. To probe this question, we have analyzed seven different ruthenium benzylidene complexes for ATR reactivity. Kinetic studies by 1 H NMR revealed that ruthenium benzylidene complexes are rapidly converted into new ATRA-active, metathesis-inactive species under typical ATRA conditions. When ruthenium benzylidene complexes were activated prior to substrate addition, the resulting activated species exhibited enhanced kinetic reactivity in ATRA with no significant difference in overall product yield compared to the original complexes. Even at low temperature, where the original intact complexes did not catalyze the reaction, pre-activated catalysts successfully reacted. Only the ruthenium benzylidene complexes that could be rapidly transformed into ATRA-active species could successfully catalyze ATRP, whereas other complexes preferred redox-initiated free radical polymerization. Kinetic measurements along with additional mechanistic and computational studies show that a metathesis-inactive ruthenium species, generated in situ from the ruthenium benzylidene complexes is the active catalyst in ATR reactions. Based on data from 1 H, 13 C, and 31 P NMR spectroscopy, and X-ray crystallography, we suspect that this ATRA-active species is a RuxCly(PCy3)z complex.

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“…The catalytic properties of the complexes can be modulated by varying the basicity and steric volume of the phosphine ligands. 13 In this sense, in the present study we report the comparative catalytic activity of complexes 1 and 2 in the styrene polymerization by ATRP.…”

Section: Introductionmentioning

confidence: 85%

“…Molecular weights were determined relative to polystyrene standards (1 × 10 6 -400 Daltons). NMR spectra were recorded on a Jeol Eclipse 300 + instrument operating at 7.05 T in CDCl 3 solvent at 25 °C, for 1 H at 300 MHz and referenced to internal CHCl 3 ; for 13 C at 75.4 MHz and referenced to internal CDCl 3 ; for 31 P at 121.4 MHz and referenced to external 85% H 3 PO 4 . For the analysis of end groups, 30 mg of sample were employed to collect the 1 H NMR spectra using about 64 scans.…”

Section: Characterizationmentioning

confidence: 99%

Comparative study of the catalytic activity of the complexes Cp*RuCl(PAr3)2 [Ar = -C6H5 and 4-CF3-C6H4] in the ATRP of styrene

Villa-Hernandez¹,

Rosales-Velázquez²,

Saldívar‐Guerra³

et al. 2011

J. Braz. Chem. Soc.

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A polimerização do estireno por ATRP foi conduzida usando os complexos Cp*RuCl(PPh 3 ) 2 , e Cp*RuCl[P(4-CF 3 −C 6 H 4 ) 3 ] 2 como catalisadores, a fim de avaliar a influência das propriedades eletrônicas dos ligantes fosfinas na velocidade e controle da polimerização. Os dados cinéticos para polimerizações realizadas com Cp*RuCl(PPh 3 ) 2 , mostram que os pesos moleculares aumentam linearmente com a conversão, com uma eficiência média de iniciação, de 0,77. Os pesos moleculares obtidos no estudo cinético com Cp*RuCl[P(4-CF 3 −C 6 H 4 ) 3 ] 2 também aumentam com a conversão, mas mostram um marcado desvio abaixo dos pesos moleculares teóricos. Este comportamento foi explicado pela oxidação gradual, irreversível do catalisador Cp*RuCl[P(4-CF 3 −C 6 H 4 ) 3 ] 2 , como confirmado pela espectroscopia de RMN de 31 P. O catalisador Cp*RuCl(PPh 3 ) 2 promove a polimerização com uma velocidade maior do que usando Cp*RuCl[P(4-CF 3 −C 6 H 4 ) 3 ] 2 , o que é consistente com as melhores propriedades de doação de elétrons de PPh 3 versus P(4-CF 3 −C 6 H 4 ) 3 . Estudos preliminares da polimerização do estireno com ATRP em CO 2 supercrítico mostram que somente o catalisador Cp*RuCl[P(4-CF 3 −C 6 H 4 ) 3 ] 2 , com ligantes fluorados, é ativo.Styrene polymerization by ATRP was conducted independently using the complexes Cp*RuCl(PPh 3 ) 2 , and Cp*RuCl[P(4-CF 3 −C 6 H 4 ) 3 ] 2 as catalysts, in order to evaluate the influence of the electronic properties of the phosphine ligands on the rate and control of the polymerization. The kinetic data for polymerizations carried out with Cp*RuCl(PPh 3 ) 2 , show that molecular weights increase linearly with conversion with an average initiation efficiency of 0.77. The molecular weights obtained in the kinetic study with Cp*RuCl[P(4-CF 3 −C 6 H 4 ) 3 ] 2 also increase with conversion but show a marked deviation below the theoretical molecular weights. This behavior was explained by the gradual, irreversible, oxidation of catalyst Cp*RuCl[P(4-CF 3 −C 6 H 4 ) 3 ] 2 as confirmed by 31 P-NMR spectroscopy. Catalyst Cp*RuCl(PPh 3 ) 2 promotes the polymerization with a rate of polymerization higher than that obtained using Cp*RuCl[P(4-CF 3 −C 6 H 4 ) 3 ] 2 ; this is consistent with the better electron donating properties of PPh 3 versus P(4-CF 3 −C 6 H 4 ) 3 . Preliminary studies of styrene polymerization by ATRP in supercritical CO 2 , shows that only catalyst Cp*RuCl[P(4-CF 3 −C 6 H 4 ) 3 ] 2 , with fluorinated ligands, was active.Keywords: atom transfer radical polymerization (ATRP), half sandwich ruthenium catalysts, styrene polymerization, supercritical carbon dioxide IntroductionHalf sandwich organometallic complexes containing transition metal from group 8 (Fe 1,2 and Ru 3-10 ) are an important group of catalysts in the polymerization of vinyl monomers by ATRP. The reversible, one electron oxidation-reduction that these complexes experience during controlled radical polymerization, promotes the establishment of a dynamic equilibrium between active and dormant species, with equilibrium con...

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Highly efficient Kharasch addition catalysed by RuCl(Cp*)(PPh3)2

Cited by 67 publications

References 11 publications

Atom Transfer Radical Reactions as a Tool for Olefin Functionalization – On the Way to Practical Applications

Atom Transfer Radical Reactions as a Tool for Olefin Functionalization – On the Way to Practical Applications

In Situ Catalyst Modification in Atom Transfer Radical Reactions with Ruthenium Benzylidene Complexes

Comparative study of the catalytic activity of the complexes Cp*RuCl(PAr3)2 [Ar = -C6H5 and 4-CF3-C6H4] in the ATRP of styrene

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