Palladium-Catalyzed Coupling of 3-Indolyl Triflate. Syntheses of 3-Vinyl and 3-Alkynylindoles

Gribble, Gordon W.; Conway, Samuel C.

doi:10.1080/00397919208019065

Cited by 40 publications

(9 citation statements)

References 29 publications

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“…3 In our hands, the reaction of 3-indolyl triflate with 2 under the conditions reported by Gribble proceeded in only 35% isolated yield, prompting further study.…”

Section: Introductionmentioning

confidence: 58%

Development of an Anomalous Heck Reaction: Skeletal Rearrangement of Divinyl and Enyne Carbinols

Sarpong

2005

Org. Lett.

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A general set of conditions that achieves the union of aryl halides and divinyl or enyne carbinols to afford tri-or tetrasubstituted olefins in good yields (up to 83%) is described. The mechanism by which this proceeds is believed to involve the intermediacy of a cyclopropanol, followed by a novel skeletal reorganization. The ability to suppress β-hydride elimination of organopalladium intermediates appears to be critical to the success of these processes.The formation of carbon-carbon bonds is of fundamental importance in the synthesis of complex organic molecules. Among the metal-catalyzed methods available for C-C bond construction, the Heck reaction is arguably one of the most useful because it employs relatively stable and easily accessible starting materials. 1 As part of a general synthetic program aimed at the facile construction of seven-membered ring containing compounds (e.g., 3, Scheme 1), we became interested in utilizing a Stille-Ortar variant 2 of the Heck reaction that employed ditriflate 1 and divinyl carbinols (e.g., 2) for this purpose. Surprisingly, a complex mixture, which included enal and bisenal products (4 and 5, respectively), was realized under standard Heck reaction conditions employing PdCl 2 (PPh 3 ) 2 (3 mol %) and Hünig's base (3 equiv) at 80 °C with DMF as solvent.We decided to pursue this transformation further with the aim of developing a wide-ranging and high-yielding method as well as added insight into the mechanism of this novel rearrangement. However, the reaction of 2 with a variety of simple aryl halides and triflates was found not to be general, as these predominantly formed the standard Heck products.Perusal of the literature revealed a single, isolated example of this reaction reported by Gribble as part of a study of the Pd-mediated synthesis of 3-vinyl and 3-alkynyl indoles. 3 In our hands, the reaction of 3-indolyl triflate with 2 under the conditions reported by Gribble proceeded in only 35% isolated yield, prompting further study.

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“…3 In our hands, the reaction of 3-indolyl triflate with 2 under the conditions reported by Gribble proceeded in only 35% isolated yield, prompting further study.…”

Section: Introductionmentioning

confidence: 58%

Development of an Anomalous Heck Reaction: Skeletal Rearrangement of Divinyl and Enyne Carbinols

Sarpong

2005

Org. Lett.

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“…Soon after, Mn(acac) 3 -mediated β-keto radical addition into N-arylacrylamides to form oxindoles was reported by Dai and co-workers (Scheme 86). 199 In this work, they also found that biaryl isocyanides (377) were good coupling partners, and addition of the β-keto radical into the isocyanide followed by trapping of the resulting radical by the aromatic ring resulted in the desired carbon−carbon bond formation. Further oxidation to regenerate aromaticity resulted in the formation of substituted phenanthridines (378,Scheme 86).…”

Section: Peroxide and Epoxide Formationmentioning

confidence: 99%

“…A related transformation had been described by Conway and Gribble in 1992 in their report of a Pd-catalyzed Heck-type coupling (Scheme ). Using aryl halides 860 and divinyl carbinols 861 , the authors propose the formation of complex 863 resulting from migratory insertion. Subsequent intramolecular migratory insertion of 863 gives rise to cyclopropyl alcohol intermediate 865 via the transition state 864 .…”

Section: Othermentioning

confidence: 99%

Selective Carbon–Carbon Bond Cleavage of Cyclopropanols

et al. 2020

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The carbon–carbon (C–C) bond cleavage of cyclopropanols is a wide area of research with much current activity. This review highlights new developments in this area over the past two decades. A summary is made of the three main reactivity modes, namely, homoenolate chemistry, β-keto radical chemistry, and acid-catalyzed ring-opening, as well as all other methods for the C–C bond cleavage and functionalization of cyclopropanols, including base-mediated ring-opening, metal-catalyzed C–C insertions and eliminations, oxidative fragmentation using hypervalent iodine reagents, reactions of donor–acceptor cyclopropanols, and pericylic reactions. Emphasis is placed on the synthetic utility of cyclopropanols and related derivatives, which have emerged as unique three-carbon synthons.

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“…Other indolyl halides and triflates were subsequently utilized as indolyl donors in palladium-catalyzed Heck reactions with terminal olefins. 7-Iodoindole was treated with methyl acrylate to give methyl 3-(indol-7-yl)-acrylate in excellent yield,154a N -tosyl-4-bromoindole was treated with methyl α-acetamidoacrylate to give the corresponding vinylic substitution product in 57% yield,154b 3-substituted-2-iodoindoles were converted into the corresponding 2,3-disubstituted indoles, N -(tosyl)indol-3-yl triflate gave 3-vinylic indoles with a number of electron-poor and neutral olefins, while the corresponding 2-carboxylate derivative did not give satisfactory results …”

Section: 21 Reaction With Alkenesmentioning

confidence: 99%

Synthesis and Functionalization of Indoles Through Palladium-catalyzed Reactions

2005

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Palladium-Catalyzed Coupling of 3-Indolyl Triflate. Syntheses of 3-Vinyl and 3-Alkynylindoles

Cited by 40 publications

References 29 publications

Development of an Anomalous Heck Reaction: Skeletal Rearrangement of Divinyl and Enyne Carbinols

Development of an Anomalous Heck Reaction: Skeletal Rearrangement of Divinyl and Enyne Carbinols

Selective Carbon–Carbon Bond Cleavage of Cyclopropanols

Synthesis and Functionalization of Indoles Through Palladium-catalyzed Reactions

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