Journal ArticleDOI
An approach to 2,3-dihydropyrroles and β-iodopyrroles based on 5-endo-dig cyclisations
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TLDR
A representative series of homopropargylic sulfonamides 19 and 22b have been found to undergo smooth 5-endo-dig cyclisation upon exposure to excess iodine in acetonitrile containing potassium carbonate.Abstract:
A representative series of homopropargylic sulfonamides 19 and 22b have been found to undergo smooth 5-endo-dig cyclisation upon exposure to excess iodine in acetonitrile containing potassium carbonate. The resulting 4-iodo-2,3-dihydropyrroles 23 readily react with two equivalents of DBU in DMF at 20 °C to give the corresponding β-iodopyrroles 24 and 26 in excellent yields by the elimination of toluene-p-sulfinic acid. Use of less than two equivalents of base results in some loss of iodine. The iodo-2,3-dihydropyrroles 23 can be used in palladium-catalysed coupling reactions as shown by the efficient formation of the Sonogashira product 29 under
mild conditions.read more
Citations
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Journal ArticleDOI
Synthesis of heterocycles via electrophilic cyclization of alkynes containing heteroatom.
Journal ArticleDOI
Cyclizations of Alkynes: Revisiting Baldwin’s Rules for Ring Closure
Kerry Gilmore,Igor V. Alabugin +1 more
Journal ArticleDOI
Synthesis of 3-iodoindoles by electrophilic cyclization of N,N-dialkyl-2-(1-alkynyl)anilines.
Dawei Yue,Richard C. Larock +1 more
TL;DR: A wide variety of N-alkyl-3-iodoindoles are readily prepared under very mild reaction conditions by the palladium/copper-catalyzed cross-coupling of N,N-dialkyl-o-iodoanilines and terminal alkynes, followed by electrophilic cyclization by I(2)(.
Journal ArticleDOI
Efficient syntheses of heterocycles and carbocycles by electrophilic cyclization of acetylenic aldehydes and ketones.
TL;DR: Highly substituted oxygen heterocycles can be prepared in good yields at room temperature by reacting o-(1-alkynyl)-substituted arene carbonyl compounds with NBS, I(2), ICl, p-O(2)NC(6)H(4)SCl, or PhSeBr and various alcohols or carbon-based nucleophiles.
Journal ArticleDOI
5-Endo-dig electrophilic cyclization of 1,4-disubstituted but-3-yn-1-ones: regiocontrolled synthesis of 2,5-disubstituted 3-bromo- and 3-iodofurans.
TL;DR: 5-Endo-dig electrophilic cyclization of 1,4-diaryl but-3-yn-1-ones with N-bromosuccinimide or N-iodosucc inimide/acetone and iodine monochloride/CH(2)Cl(2), at room temperature, in the absence of base, provides 3-halo-2,5-diaries with excellent regiocontrol and high yields.
References
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Journal ArticleDOI
A mild and efficient route to Schiff base derivatives of amino acids
Martin J. O'Donnell,Robin Polt +1 more
Journal ArticleDOI
A useful synthesis of pyrroles from nitroolefins
Derek H. R. Barton,Derek H. R. Barton,J. Kervagoret,J. Kervagoret,Samir Z. Zard,Samir Z. Zard +5 more
TL;DR: In this article, it was shown that β-acetoxy-nitro compounds react with α-isocyano-esters in the presence of an organic base to give pyrroles in good yield.
Journal ArticleDOI
N-(Triisopropylsilyl)pyrrole. A progenitor "par excellence" of 3-substituted pyrroles
Brian L. Bray,Peter H. Mathies,Reto Naef,Dennis Solas,Thomas T. Tidwell,Dean R. Artis,Joseph M. Muchowski +6 more
TL;DR: In this article, a most useful strategy has been devised for the synthesis of 3-substituted pyrroles on the basis of the kinetic electrophilic substitution of 1-(triisopropylsilyl) pyrrole (1) at the β position and subsequent fluoride ion induced desilylation.
Journal ArticleDOI
Synthesis of 3-arylpyrroles and 3-pyrrolylacetylenes by palladium-catalyzed coupling reactions
TL;DR: In this article, the palladium-catalyzed coupling of appropriate 1-(triisopropylsilyl)-3-substituted pyrroles with aryl halides or monosubstitized acetylenes and subsequent tetrabutylammonium fluoride desilylation is described.
Journal ArticleDOI
Inter- and intramolecular addition/cyclizations of sulfonamide anions with alkynyliodonium triflates. Synthesis of dihydropyrrole, pyrrole, indole, and tosylenamide heterocycles
TL;DR: In this paper, the synthesis of dihydropyrroles, pyrrole, and indoles through [3-atom + 2-atom] combination of ethyl or aryl tosylamide anions with phenyl(propynyl)iodonium triflate is described.
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