Stereoselective synthesis of Z-enol esters catalysed by [bis(diphenylphosphino)alkane]bis(2-methylpropenyl)ruthenium complexes

Doucet, Henri; Höfer, Jürgen; Bruneau, Christian; Dixneuf, Pierre H.

doi:10.1039/c39930000850

Cited by 75 publications

(21 citation statements)

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“…Ru(methallyl) 2 (diphenylphosphanylalkane) proved to be successful and provided the first metal catalysts that favored the anti-Markovnikov addition of carboxylic acids to terminal alkynes to form Z and E enol esters with high regioselectivity (Scheme 7). [74] The best catalyst precursors were [Ru(methallyl) 2 (dppb)] (I; dppb = diphenylphosphanylbutane) and [Ru(methallyl) 2 -(dppe)] (II; dppe = diphenylphosphanylethane), which also led to a remarkable stereoselectivity in favor of the Z isomer; the overall reaction thus corresponds to a formal trans addition of RC(O)O-H to the triple bond. The formation of a vinylidene intermediate according to a mechanism proposed by Wakatsuki by initial protonation of the ruthenium center [75] cannot be excluded.…”

Section: Catalytic Addition Of Carboxylic Acids To Alkynes: a Convenimentioning

confidence: 98%

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

2006

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The involvement of a catalytic metal vinylidene species was proposed for the first time in 1986 to explain the regioselective formation of vinyl carbamates directly from terminal alkynes, carbon dioxide, and amines. Since this initial report, various metal vinylidenes and allenylidenes, which are key activation intermediates, have proved extremely useful for many alkyne transformations. They have contributed to the rational design of new catalytic reactions. This 20th anniversary is a suitable occasion to present the advancement of organometallic vinylidenes and allenylidenes in catalysis.

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Section: Catalytic Addition Of Carboxylic Acids To Alkynes: a Convenimentioning

confidence: 98%

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

2006

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“…A typical procedure is as follows: 1.0 g of metal oxide was added to a solution of 79 mg (0.20 mmol, 20 mg as Ru) of Ru(acac) 3 in 10 cm 3 of THF under air at room temperature. For Ru 3 (CO) 12 and [RuCl 2 (CO) 3 ] 2 , THF was used as a solvent, while RuCl 3 ·nH 2 O and [RuCl 2 (p-cymene)] 2 were impregnated from their methanol solutions. After impregnation and drying overnight in air at 80°C, the resulting powder was calcined in air at 400°C for 30 min to afford the Ru(2.0 wt %)/support catalyst.…”

Section: ■ Experimental Sectionmentioning

confidence: 99%

Active Ruthenium Catalysts Based on Phosphine-Modified Ru/CeO₂for the Selective Addition of Carboxylic Acids to Terminal Alkynes

et al. 2012

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The modification of ruthenium species supported on ceria in the presence of suitable phosphines under H 2 at 100°C was found to generate catalytically active Ru species that were effective for the regio-and stereoselective addition of carboxylic acids to terminal alkynes. The reactions in the presence of a catalytic amount of Ru/CeO 2 modified with 1,4-bis(diphenylphosphino)butane gave the anti-Markovnikov adducts in high yields with excellent (Z)-isomer selectivities. On the other hand, the reactions with the trioctylphosphine-modified catalyst gave the Markovnikov adducts as major products. Among the catalysts examined, only ceriaor zirconia-supported catalysts were effective, and hot filtration tests using the phosphine-modified Ru/CeO 2 catalyst suggested that soluble ruthenium species showed quite a high catalytic activity. Very small amounts of ruthenium species were detected in the solution. The solid Ru/CeO 2 could be repeatedly used as a reservoir of active catalysts without a significant loss of activity. ■ INTRODUCTIONThe development of highly selective catalytic reactions with high atom efficiencies is quite important, since such processes should give the desired products without byproduct or waste. 1 To achieve such goals, transition-metal complexes have been widely applied as homogeneous catalysts, mainly because finetuning of their active sites by ligands or additives can induce excellent activities and selectivities. In this context, rutheniumcomplex catalysts together with suitable phosphine ligands have been used to achieve the regio-and stereoselective addition of carboxylic acid to alkynes, 2−21 which is the most atomeconomical route for the synthesis of vinyl esters. 22−31 The use of solid catalysts, particularly oxide-supported metal catalysts, is quite attractive because of their simple preparation, high stability, and facile reusability, as well as minimal contamination of the products by metallic species. 32−41 Recently, we developed recyclable Ru/CeO 2 catalysts that are quite effective for various C−C bond-forming reactions. 42−47 Our latest spectroscopic investigations showed that Ru(IV)O species on CeO 2 were transformed into low-valent Ru species with high catalytic activities. 46,47 In the course of these studies, we found that the heating of Ru/CeO 2 catalysts in a hydrogen atmosphere in the presence of a small amount of phosphines (phosphine modification route) greatly improved the activities of the resulting Ru catalysts for the arylation 44 and alkylation 45 of aromatic C−H bonds. Furthermore, unmodified Ru/CeO 2 catalysts were found to be effective for the addition of carboxylic acids to terminal alkynes to give the (E)-isomer of vinyl esters as major products. 48 On the basis of these results as well as those using immobilized Ru catalysts, 49 we expected the modification of Ru/CeO 2 by suitable phosphines to generate highly active Ru catalysts for the regio-and stereoselective synthesis of vinyl esters via the addition of carboxylic acids to alkynes.We report here a simple...

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“…For example, benzoic acid added in a regio-and stereoselective manner to phenylacetylene (equation 1), [17] n-hexyne (equation 2), [18] and 2-methyl-1-buten-3-yne (equation 3) [19] to give the corresponding enol esters in excellent yields (Scheme 11).…”

Section: Carbamate Nucleophilesmentioning

confidence: 99%

Metal Vinylidenes as Catalytic Species in Organic Reactions

Trost

McClory

2008

Chemistry An Asian Journal

189

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Organic vinylidene species have found limited use in organic synthesis due to their inaccessibility. In contrast, metal vinylidenes are much more stable, and may be readily accessed through transition metal activation of terminal alkynes. These electrophilic species may be trapped by a number of nucleophiles. Additionally, metal vinylidenes can participate in pericyclic reactions and processes involving migration of a metal ligand to the vinylidene species. This review addresses the reactions and applications of metal vinylidenes in organic synthesis.

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Stereoselective synthesis of Z-enol esters catalysed by [bis(diphenylphosphino)alkane]bis(2-methylpropenyl)ruthenium complexes

Abstract: Re n n es, France Z-Enol esters are obtained via regio-and stereo-selective addition of carboxylic acids to terminal alkynes, with formation of a C( 1 ) carbon-oxygen bond, in the presence of a [Ru{ Ph2P(CH2),PPh2} { T ~-C H ~-C ( M ~) = C H ~} ~I catalyst precursor.

Cited by 75 publications

References 9 publications

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

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

Active Ruthenium Catalysts Based on Phosphine-Modified Ru/CeO₂for the Selective Addition of Carboxylic Acids to Terminal Alkynes

Metal Vinylidenes as Catalytic Species in Organic Reactions

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Stereoselective synthesis of Z-enol esters catalysed by [bis(diphenylphosphino)alkane]bis(2-methylpropenyl)ruthenium complexes

Abstract: Re n n es, France Z-Enol esters are obtained via regio-and stereo-selective addition of carboxylic acids to terminal alkynes, with formation of a C( 1 ) carbon-oxygen bond, in the presence of a [Ru{ Ph2P(CH2),PPh2} { T ~-C H ~-C ( M ~) = C H ~} ~I catalyst precursor.

Cited by 75 publications

References 9 publications

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

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

Active Ruthenium Catalysts Based on Phosphine-Modified Ru/CeO2for the Selective Addition of Carboxylic Acids to Terminal Alkynes

Metal Vinylidenes as Catalytic Species in Organic Reactions

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Active Ruthenium Catalysts Based on Phosphine-Modified Ru/CeO₂for the Selective Addition of Carboxylic Acids to Terminal Alkynes