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Intramolecular reaction
About: Intramolecular reaction is a research topic. Over the lifetime, 5015 publications have been published within this topic receiving 138213 citations.
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TL;DR: In this article, a modele permet de prevoir de facon precise la regioselectivite et la stereoselective des reactions de cyclisation des radicaux alkyles.
Abstract: Ce modele permet de prevoir de facon precise la regioselectivite et la stereoselectivite des reactions de cyclisation des radicaux alkyles
452 citations
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TL;DR: A general method for the formation of benzoxazoles via a copper-catalyzed cyclization of ortho-haloanilides is reported, and is believed to proceed via an oxidative insertion/reductive elimination pathway through a Cu(I)/Cu(III) manifold.
Abstract: A general method for the formation of benzoxazoles via a copper-catalyzed cyclization of ortho-haloanilides is reported. This approach complements the more commonly used strategies for benzoxazole formation which require 2-aminophenols as substrates. The reaction involves an intramolecular C−O cross-coupling of the ortho-haloanilides and is believed to proceed via an oxidative insertion/reductive elimination pathway through a Cu(I)/Cu(III) manifold. The reaction is also applicable to the formation of benzothiazoles. A variety of ligands including 1,10-phenanthroline and N,N‘-dimethylethylenediamine were shown to provide ligand acceleration/stabilization in the reaction. Optimal conditions for cyclization used a catalyst combination of CuI and 1,10-phenanthroline (10 mol %). The method was amenable to a parallel-synthesis approach, as demonstrated by the synthesis of a library of benzoxazoles and benzothiazoles substituted at various positions in the ring. Most examples utilized the cyclization of ortho-br...
442 citations
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TL;DR: Substituted pyrroles were prepared by a gold(I)-catalyzed acetylenic Schmidt reaction of homopropargyl azides to allow for regiospecific substitution at each position of the pyrrole ring under mild conditions.
Abstract: Substituted pyrroles were prepared by a gold(I)-catalyzed acetylenic Schmidt reaction of homopropargyl azides. The reaction allows for regiospecific substitution at each position of the pyrrole ring under mild conditions. A mechanism in which azides serve as nucleophiles toward gold(I)-activated alkynes with subsequent gold(I)-aided expulsion of dinitrogen is proposed.
421 citations
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TL;DR: These results provide the foundation of a unified enamine catalysis mechanism of proline-catalyzed inter- and intramolecular aldol reactions, and are supported by B3LYP/6-31G* calculations.
Abstract: Contrary to the widely accepted mechanism of the Hajos−Parrish−Eder−Sauer−Wiechert reaction, we have obtained evidence for the involvement of only one proline molecule in the transition states of both inter- and intramolecular aldol reactions. Our conclusions are based on kinetic measurements and the absence of nonlinear and dilution effects on the asymmetric catalysis, and are supported by B3LYP/6-31G* calculations. Complementary to recent theoretical studies, our results provide the foundation of a unified enamine catalysis mechanism of proline-catalyzed inter- and intramolecular aldol reactions.
421 citations
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TL;DR: A Au(I)-catalyzed intramolecular hydroamination of N-allenyl carbamates tolerated substitution at the alkyl and allenyl carbon atoms and was effective for the formation of piperidine derivatives and the corresponding oxygen heterocycles in good yield with high exo-selectivity.
Abstract: Reaction of benzyl (2,2-diphenyl-4,5-hexadienyl)carbamate (4) with a catalytic 1:1 mixture of Au[P(t-Bu)2(o-biphenyl)]Cl (2) and AgOTf (5 mol %) in dioxane at 25 °C for 45 min led to isolation of benzyl 4,4-diphenyl-2-vinylpyrrolidine-1-carboxylate (5) in 95% yield. The Au(I)-catalyzed intramolecular hydroamination of N-allenyl carbamates tolerated substitution at the alkyl and allenyl carbon atoms and was effective for the formation of piperidine derivatives. γ-Hydroxy and δ-hydroxy allenes also underwent Au-catalyzed intramolecular hydroalkoxylation within minutes at room temperature to form the corresponding oxygen heterocycles in good yield with high exo-selectivity. 2-Allenyl indoles underwent Au-catalyzed intramolecular hydroarylation within minutes at room temperature to form 4-vinyl tetrahydrocarbazoles in good yield. Au-catalyzed cyclization of N-allenyl carbamates, allenyl alcohols, and 2-allenyl indoles that possessed an axially chiral allenyl moiety occurred with transfer of chirality from the...
401 citations