35246-18-5Relevant academic research and scientific papers
Iridium- and ruthenium-catalysed synthesis of 2,3-disubstituted indoles from anilines and vicinal diols
Tursky, Matyas,Lorentz-Petersen, Linda L. R.,Olsen, Lasse B.,Madsen, Robert
experimental part, p. 5576 - 5582 (2011/02/18)
A straightforward and atom-economical method is described for the synthesis of 2,3-disubstituted indoles. Anilines and 1,2-diols are condensed under neat conditions with catalytic amounts of either [Cp*IrCl2] 2/MsOH or RuCl3·xH2O/phosphine (phosphine = PPh3 or xantphos). The reaction does not require any stoichiometric additives and only produces water and dihydrogen as byproducts. Anilines containing methyl, methoxy, chloro and fluoro substituents can participate in the cyclocondensation. Meta-substituted anilines give good regioselectivity for 6-substituted indoles, while unsymmetrical diols afford excellent regioselectivity for the indole isomer with an aryl or large alkyl group in the 2-position. The mechanism for the cyclocondensation presumably involves initial formation of the α-hydroxyketone from the diol. The ketone subsequently reacts with aniline to generate the α-hydroxyimine which rearranges to the corresponding α-aminoketone. Acid- or metal-catalysed electrophilic ring-closure with the release of water then furnishes the indole product.
Zn(OTf)2-catalyzed cyclization of proparyl alcohols with anilines, phenols, and amides for synthesis of indoles, benzofurans, and oxazoles through different annulation mechanisms
Kumar, Manyam Praveen,Liu, Rai-Shung
, p. 4951 - 4955 (2007/10/03)
Zn(OTf)2 (10 mol %) catalyzed the cyclization of propargyl alcohols with PhXH (X = O, NH) in hot toluene (100 °C) without additive and gave indole and benzofuran products with different structures. In such transformations, α-carbonyl intermedia
Intramolecular cyclization reactions of unsaturated amino Fischer chromium carbenes forming indoles and quinolines
S?derberg, Bj?rn C. G.,Shriver, James A.,Cooper, Seth H.,Shrout, Timothy L.,Helton, E. Scott,Austin, Lucinda R.,Odens, Herman H.,Hearn, Brian R.,Jones, Paula C.,Kouadio, Tiara N.,Ngi, Tan H.,Baswell, Rachel,Caprara, H. John,Meritt, Mark D.,Mai, Than T.
, p. 8775 - 8791 (2007/10/03)
A thermally induced intramolecular annulation reaction of N-(2-alkenylphenyl)amino substituted Fischer chromium carbenes has been extensively examined. The carbene complexes were prepared in moderate to good yields by reaction of 2-aminostyrenes with intermediately formed acyloxy substituted carbenes. Upon heating, the thermally labile carbenes decomposed producing indoles and quinolines as the major products. The product distribution was found to be highly dependent on the substitution pattern and electronic properties of the starting material, and on the solvent used.
A practical one-pot synthesis of 2,3-disubstituted indoles from unactivated anilines
Tokunaga, Makoto,Ota, Mitsuru,Haga, Masa-aki,Wakatsuki, Yasuo
, p. 3865 - 3868 (2007/10/03)
2-Substituted-3-methyl indoles are synthesized with good regioselectivity from readily available substrates and catalysts, i.e. the reaction of anilines with propargyl alcohols in the presence of 0.36-1 mol% Ru3(CO)12.
Synthesis of 2,3-disubstituted indoles via palladium-catalyzed annulation of internal alkynes
Larock,Yum,Refvik
, p. 7652 - 7662 (2007/10/03)
The palladium-catalyzed coupling of 2-iodoaniline and the corresponding N-methyl, -acetyl, and -tosyl derivatives with a wide variety of internal alkynes provides 2,3-disubstituted indoles in good-to-excellent yields. The best results are obtained by empl
