Ruthenium-catalysed conversion of 1,4-alkynediols into pyrroles

Synthesis of furans, pyrroles and pyridazines by a ruthenium-catalysed isomerisation of alkynediols and in situ cyclisation

“…28 There have been several other approaches to the synthesis of pyrroles from alkyne-containing precursors, including a coppercatalysed cycloisomerisation of alkynylimines, 29 palladium-catalysed cyclisation of Z-enynamines, 30 various substrates, 31 and a titanium-catalysed process involving initial hydroamination of 1,4 and 1,5-diynes with primary amines. 32 The conversion of simple diols into saturated N-substituted heterocycles using ruthenium based catalysts has been reported and is described in reviews (Scheme 5).…”

Recent Progress of New Catalytic Synthetic Methods for Nitrogen Heterocycles Based on Hydrogen Transfer Reactions

“…Various vicinal-diols were subjected to react with o-phenylenediamines in order to investigate the reaction scope (entries [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20]. The product yield was not significantly affected by the position of the substituent on the aromatic ring, whereas the electronic nature of that had some relevance to the product yield.…”

“…Williams et al also reported ruthenium-catalyzed conversion of 1,4-alkynediols into pyrroles. 19 Xantphos as ligand gave the best reactivity and selectivity in furan formation and used this ligand for pyrrole-forming reactions. Thus, various 1,2,5-substituted pyrroles have been synthesized from 1,4-alkynediols using a ruthenium catalyzed isomerization to give the corresponding 1,4-dicarbonyl compounds, which undergo in situ cyclization to pyrroles in the presence of amine.…”

Eine effiziente und allgemeine Synthese primärer Amine durch Ruthenium‐katalysierte Aminierung sekundärer Alkohole mit Ammoniak

“…Die meisten Katalysatorsysteme wurden bei 130 8C zersetzt und lieferten unbefriedigende Ergebnisse (< 5 % Cyclohexylamin). Typische ein-und zweizähnige Arylphosphane wie Triphenylphosphan (1), Xantphos [19] (4,5-Bis(diphenylphosphanyl)-9,9-dimethylxanthen;…”