Amination of aryl- and vinylacetylenic compounds catalyzed by rhodium(I) complexes

New rhodium-catalyzed amination reactions of arylacetylenes and cyclohexen-1-ylacetylene in the presence of strong bases with the use of carbon dioxide as an auxiliary are described. Secondary amines attack the terminal carbon atom of the triple bond followed by protonation of the adjacent carbon atom. Alternatively, the reaction can proceed further with the addition of the second alkyne molecule. The conditions for the selective synthesis of enamines (up to 87% yield) or α-substituted propynylamines (up to 86% yield) are reported. Dipartimento di Chimica Organica e Industriale dell'Università, Viale delle Scienze, I-43100 Parma, Italia. Dipartimento di Chimica, Università della Calabria, Arcavacata di Rende, I-80036 Cosenza, Italia. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 966–970, May, 1998.     

2,2,2-Trichloro-4-methoxy-1,3,2-benzodioxaphosphole in the reactions with terminal acetylenes

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The structure of products of reaction ofo-phenylenedioxytrichlorophosphorane with arylacetylenes

The products of reaction ofo-phenylenedioxytrichlorophosphorane with arylacetylenes were identified as 4-aryl-2-chloro-2-oxo-5,6-(4-chlorobenzo)phosphorin-3-enes using¹H,¹³C,³¹P NMR, and IR spectroscopy and high-resolution mass spectrometry. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 368–370, February, 1997.     

Unexpected cyclization route for o-ethynylbenzoic acids hydrazides in the presence of base

The reaction of o-ethynylbenzoic acids hydrazides with base has been studied. In the presence of a strong donor substituent (1,5-dimethylpyrazol-4-yl) it has been found that an unusual cyclization route occurs to give the corresponding benzopyridazinone instead of the expected isoindolinone. Dedicated to Academician B. A. Trofimov in his 70^th jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 67-70, January, 2009.     

Magnetically recyclable Cu-BTC@Fe3O4-catalyzed synthesis of aryl α-chlorobenzyl ketones

Metal–organic framework (MOF) composite, viz. Cu-BTC@Fe₃O₄ (BTC is 1,3,5-benzenetricarboxylate), was prepared and utilized for the synthesis of aryl α-chlorobenzyl ketones from arenediazonium salts and arylacetylenes in moderate to good yields. This reaction proceeded via a radical domino process. The catalyst could be readily recovered with an external permanent magnet, with slight decrease in its activity after successive six runs.     

Synthesis of polyarylacetylenes by γ‐ray‐induced polymerization of terminal alkynes. Nanostructures of ortho‐substituted derivatives

Terminal aryl alkynes RC₆H₄C?CH with substituents of different electronic properties and ring position (R = H, 4‐CF₃, 4‐OMe, 2‐CF₃, 2‐OMe, 2‐Me) were exposed to γ‐radiation (50–400 kGy) in organic solvents (hexane, 1,4‐dioxane, ethylacetate, methanol, tetrahydrofuran), at room temperature. The effects arising from substituent, solvent, dilution, and radiation dose allowed to define the conditions suitable for polymerization, which was favored in methanol at increasing dilution of the alkyne. Ortho‐substitution represented the key structural element in the substrate, and the derived polyarylacetylenes were characterized in detail, including gel permeation chromatography, thermal analysis, infrared, NMR, UV–vis, fluorescence, and scanning electron microscope spectroscopy. The results are consistent with the formation of irregular polymers mainly composed of trans‐transoid chains. Controlled aggregation of the polymers by means of an osmosis‐based procedure in solvent/non‐solvent mixtures allowed the formation of nanostructured materials, in particular of hollow nanospheres from THF/water. The methodology sets the basis for the development of γ‐rays‐induced polymerization of alkynes, in a transition metal catalyst‐free environment. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012