Halo- and selenolactonisation: the two major strategies for cyclofunctionalisation

Ranganathan, Subramania; Muraleedharan, K.; Vaish, Narendra K.; Jayaraman, Narayanaswamy

doi:10.1016/j.tet.2004.04.014

Cited by 242 publications

(85 citation statements)

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“…59 The initial studies were focused on the development of an optimum set of reaction conditions for the coupling reactions of vinylic chalcogenides with Grignard reagents. We chose (E)-phenyl(styryl)tellane (1d) and a THF solution of n-octyl magnesium bromide as starting materials, searching for the best solvent and the amount of Fe(acac) 3 , performing the reactions at room temperature (Tables 1 and 2). …”

Section: Resultsmentioning

confidence: 99%

“…At first, we found that by using 10 mol% of Fe(acac) 3 , in benzene, the (E)-dec-1-enylbenzene (3e) was obtained in 12% yield after stirring for 3 h (Table 1, entry 1). We also evaluated other solvents, such as THF and NMP (Table 1, entries 2 and 3).…”

Section: Resultsmentioning

confidence: 99%

“…When the reaction was carried out without catalyst no product was obtained ( Table 2, entry 1). The use of 5 mol% of Fe(acac) 3 produced 3e in 48% yield ( Table 2, entry 2). The use of larger amounts of catalyst had no effect on the yield of reaction and the required time to completion of reaction was the same (Table 2, entry 4).…”

Section: Resultsmentioning

confidence: 99%

“…The multiple applications of organochalcogenium chemistry have been well described in a number of review articles [1][2][3][4][5][6] and books. [7][8][9][10][11] Functionalized alkynyl [12][13][14][15][16][17][18] and alkenyl [19][20][21][22][23] chalcogenides have a great potential in organic synthesis, since they are valuable intermediates for the selective preparation of several organic compounds.…”

Section: Introductionmentioning

confidence: 99%

“…21, No. 11, 2010 using [Fe(acac) 3 ], (acac: acetylacetonate), since it is a very stable, cheap and easy to prepare catalyst. 59 The initial studies were focused on the development of an optimum set of reaction conditions for the coupling reactions of vinylic chalcogenides with Grignard reagents.…”

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Iron-catalyzed coupling reactions of vinylic chalcogenides with Grignard reagents

Silveira¹,

Mendes²,

Wolf³

2010

J. Braz. Chem. Soc.

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Este trabalho descreve um novo método para a reação de acoplamento entre selenetos e teluretos vinílicos e reagentes de Grignard, catalisada por Fe(acac) 3 e à temperatura ambiente. A reação ocorre com retenção da configuração, fornecendo os respectivos alquenos em bons a excelentes rendimentos. Este método também é eficiente para a reação de acoplamento de calcogenetos bisvinílicos com reagentes de Grignard.A general new method for the cross-coupling reaction between vinylic selenides and tellurides and Grignard reagents catalyzed by Fe(acac) 3 at room temperature is described. This reaction proceeded with retention of configuration, providing the respective alkenes in good to excellent yields. This method is also efficient for the coupling reaction of divinyl chalcogenides with Grignard reagents. Keywords: iron-catalyzed, vinylic chalcogenides, cross-coupling, Grignard reagents IntroductionOrganochalcogenium compounds became the key component of a variety of versatile and useful reagents for organic synthesis. The multiple applications of organochalcogenium chemistry have been well described in a number of review articles 1-6 and books. 7-11 Functionalized alkynyl 12-18 and alkenyl [19][20][21][22][23] chalcogenides have a great potential in organic synthesis, since they are valuable intermediates for the selective preparation of several organic compounds.Among the many applications of vinylic selenides, divinylic selenides and vinylic sulfides, the cross-coupling reaction with Grignard reagents catalyzed by Ni 18,24-27 and Pd 28,29 to give the corresponding cross-coupled products, has been described. On the other hand, Pd 19,30 and Ni 24,[31][32][33] catalyzed cross coupling reactions and tellurium/metal exchange reactions [34][35][36][37][38][39][40][41][42] are demonstrative of the usefulness of vinylic tellurides.Transition-metal-catalyzed C-C bond coupling reactions are very important in many areas of science. 43,44 Most current methods require expensive transitionmetal catalysts and ligands. However, in the last years Fe-catalyzed C-C bond cross coupling reactions of vinylic substrates and Grignard reagents became a subject of intense interest. [45][46][47][48][49][50][51] The vinylic counterpart is quite broad in scope, since vinylic halides, triflates, sulfonates, tosylates and enol phosphates can be used. [45][46][47][48][49][50][51] In continuation to our interest on the synthesis and synthetic applications of vinylic chalcogenides 52-58 we decided to study the feasibility of their use in cross coupling reaction with Grignard species catalyzed by iron. To the best of our knowledge, iron catalysts have never been used for the coupling of vinylic selenides and tellurides as electrophiles. The possible use of iron catalysts would represent a great improvement over the high cost of palladium precursors and from the concerns about the toxicity of nickel salts. In light of the above comments it is of interest to design a simple, efficient, and versatile method for the stereoselective coupling of vinylic se...

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%