Metal Vinylidenes and Allenylidenes in Catalysis: Applications in Anti‐Markovnikov Additions to Terminal Alkynes and Alkene Metathesis

Bruneau, Christian; Dixneuf, Pierre H.

doi:10.1002/anie.200501391

Cited by 466 publications

(139 citation statements)

References 318 publications

(369 reference statements)

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“…Fluctuations in the molecular weights should not be overconsidered. Unlike related cationic ruthenium [37,38] or osmium [39] complexes possessing an alkylidene, vinylidene, allenylidene, or indenylidene moiety in their coordination sphere, the ruthenium-(p-cymene) catalyst precursors examined in this study lack a suitable metal-carbene fragment to initiate olefin metathesis. Ill-defined mechanisms involving arene disengagement and monomer coordination are held responsible for their transformation into active species during the course of the reaction [40,41].…”

Section: Ring-opening Metathesis Polymerization Of Cyclooctenementioning

confidence: 97%

Imidazol(in)ium-2-carboxylates as N-heterocyclic carbene precursors in ruthenium–arene catalysts for olefin metathesis and cyclopropanation

Tudose

Demonceau

Delaude

2006

Journal of Organometallic Chemistry

120

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Section: Ring-opening Metathesis Polymerization Of Cyclooctenementioning

confidence: 97%

Imidazol(in)ium-2-carboxylates as N-heterocyclic carbene precursors in ruthenium–arene catalysts for olefin metathesis and cyclopropanation

Tudose

Demonceau

Delaude

2006

Journal of Organometallic Chemistry

120

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“…Although less active than their alkylidene counterparts, complexes featuring an Ru=C=CHR moiety are wellknown initiators for various types of olefin metathesis, including ROMP and RCM (Scheme 4). [33] We have applied this strategy to alter the course of the reaction between a,w-dienes and our homobimetallic ruthenium-arene complexes. Thus, substrates 4 and 5 were reacted with catalyst precursors 2a, 3a, and 3b (2 mol %) in the presence of phenylacetylene (6 mol %).…”

Section: Catalytic Investigationsmentioning

confidence: 99%

Homobimetallic Ruthenium–N‐Heterocyclic Carbene Complexes: Synthesis, Characterization, and Catalytic Applications

et al. 2007

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where L = 1,3-bis(2,4,6-trimethylphenyl)imidazolin-2-ylidene (3a) or 1,3-bis(2,4,6-trimethylphenyl)-4,5-dichloroimidazolin-2-ylidene (3b), were isolated in high yields upon heating a toluene solution of [RuCl 2 A C H T U N G T R E N N U N G (p-cymene)] 2 with 1 equivalent of carbene ligand under an ethylene atmosphere. They were characterized by NMR and TGA. Their catalytic activity was investigated in the atom transfer radical polymerization of vinyl monomers. In the polymerization of methyl methacrylate, complex 3a displayed faster reaction rates than 3b and the related phosphine-based complex 2a (L = tricyclohexylphosphine), although control was more effective with the latter catalyst. When n-butyl acrylate or styrene served as monomer, a major shift of reactivity was observed between complex 2a that promoted controlled radical polymerization, and complexes 3a or 3b that favored metathetical coupling. Further homocoupling experiments with various styrene derivatives confirmed the outstanding aptitude of complex 3a (and to a lesser extent of 3b) to catalyze olefin metathesis reactions. Contrary to monometallic ruthenium-arene complexes of the [RuCl 2 A C H T U N G T R E N N U N G (p-cymene)(L)] type, the new homobimetallic species did not require the addition of a diazo compound or visible light illumination to initiate the ring-opening metathesis of norbornene or cyclooctene. When a,w-dienes were exposed to 3a or 3b, a mixture of cycloisomerization and ring-closing metathesis products was obtained in a non-selective way. Addition of a terminal alkyne co-catalyst enhanced the metathetical activity while completely repressing the cycloisomerization process. Thus, quantitative conversions of diethyl 2,2-diallylmalonate and N,N-diallyltosylamide were achieved within 2 h at room temperature using 2 mol % of catalyst precursor 3 a and 6 mol % of phenylacetylene.

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“…The information about reactivity and selectivity of relay olefin metathesis in the presence of multi-double/triple bonds [22], olefin metathesis controlled by a template [23], and the catalysts for alkene as well as alkyne metathesis [24] are all well documented now.…”

Section: Olefin Metathesis Reactionmentioning

confidence: 98%

A new era for organic synthesis—highlights of the recent progress

Yikang

2007

Front. Chem. China

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The major progress in organic synthesis since 2005 is briefly surveyed in two parts. The first part deals with some of the most impressive advances in the synthetic methodology, which includes: (1) metal-mediated synthetic reactions, with an emphasis on the olefin metathesis and gold-mediated reactions; (2) free radical-based organic synthesis; (3) synthetic transformations performed in a "one-pot" manner involving either tandem reactions or multicomponent reactions; (4) asymmetric reactions catalyzed by metal and organo-catalysts. The major advances in total synthesis of some complex natural products with significant biological activities are presented in the second part, with detailed illustrations of ten selected molecules, including dragmacidin F, abyssomicin C, 11-acetoxy-4-deoxyasbestinin D, pentacycloanammoxic acid, UCS1025A, (−)-merrilactone A, nigellamine A 2 , (+)-saxitoxin, and Tamiflu (an artificially designed natural product-like molecule). An array of complicated structures of the natural products synthesized over the last two years is also listed to serve as a convenient lead to the original literature for the prospective interested readers.Keywords organic synthesis, metal-mediated synthetic reaction, free radical reaction, "in one pot" reaction, asymmetric reaction, total synthesis of natural products Organic reactions are of central importance to organic synthetic methodology and underlie all types of organic A new era for organic synthesis-highlights of the recent progress

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Metal Vinylidenes and Allenylidenes in Catalysis: Applications in Anti‐Markovnikov Additions to Terminal Alkynes and Alkene Metathesis

Cited by 466 publications

References 318 publications

Imidazol(in)ium-2-carboxylates as N-heterocyclic carbene precursors in ruthenium–arene catalysts for olefin metathesis and cyclopropanation

Imidazol(in)ium-2-carboxylates as N-heterocyclic carbene precursors in ruthenium–arene catalysts for olefin metathesis and cyclopropanation

Homobimetallic Ruthenium–N‐Heterocyclic Carbene Complexes: Synthesis, Characterization, and Catalytic Applications

A new era for organic synthesis—highlights of the recent progress

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