Cyclooligomerization of Mono- and Diazulenylethynes Catalyzed by Transition Metal Complexes

Cyclooligomerization of 1-ethynylazulenes 1a,b, 6 and 7 as well as 1,2-bis(azulen-1-yl)ethynes 10a,b and 11 with CpCo(CO)₂ to the corresponding 1,2,4-tris(azulen-1-yl)benzenes 14a,b, 18 and 19 as well as [bis- and tetrakis(azulen-1-yl)cyclobutadiene]cobalt complexes 17a,b, 30a,b and 31 is described

Synthesis and Characterization of Novel Oligoazulenes with Mixed Ethynyl and Butadiynyl Bridges

The new oligoazulenes 10–14 with mixed ethynyl and butadiynyl bridges were synthesized by oxidative Eglinton coupling from the readily accessible ethynylazulenes 3, 4, 7, 9 and 15 as well as by Pd/Cu-catalyzed cross-coupling reactions with the appropriate iodoazulenes 5, 6 and 8

Alkynylazulenes as Building Blocks for Highly Unsaturated Scaffolds

Recently developed routes to the synthesis of mono- and polyethynylated azulenes and their transformations into linear oligoazulenes with ethynyl and butadiynyl bridges as well as azulenyl-substituted benzenes, cyclobutadiene complexes, and azulene-substituted tetracyanobutadienes are reviewed. The utility of ethynylazulene derivatives for the synthesis of azulene-substituted heterocycles has also been reviewed

Efficient synthesis of novel bis(dihydropyrano[2,3c]pyrazoles), bis(4H-chromenes) and bis(dihydropyrano[3,2-c]chromenes) with amide functionality

A synthesis of novel bis(1,4-dihydropyrano[2,3-c]pyrazole-5-carbonitriles), bis(4H-chromene-3-carbonitriles) and bis(dihydropyrano[3,2-c]chromenes), which are linked to aliphatic spacers via amide linkages was achieved via multicomponent reactions (MCR) of the appropriate bis-aldehyde with two equivalents of both of malononitrile and 3-methylpyrazol-5-one, dimedone or 4-hydroxycoumarin in a basic solution

Ethynylazulenes — Building Blocks for Novel Oligoazulenes with Ethynyl and Butadiynyl Bridges

The azulenes 3a,b, 6a,b, 9, 12 and 15 ethynylated in the five-membered ring were prepared by Pd-catalysed cross-coupling of the corresponding iodoazulenes 1a,b, 4a,b, 7, 10 and 13, respectively, with trimethylsilylacetylene and subsequent desilylation. The synthesis of some acyclic oligomers 23–30, 32–36 and 38–40 from these ethynylazulenes could be accomplished by oxidative Eglinton coupling as well as Pd/Cu-catalysed cross-coupling reactions with the appropriate iodoazulenes 1a,b, 4b, 31 and 34. The UV/Vis spectra of the novel oligomers 32, 35 and 36 allow an estimation of the bandgap (Eg) of poly(1,3-azulenylethynylene)s lower than 2 eV