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Bridging pyrrole and selenophene chemistries: Molecular assemblies have been developed that allow scrutiny of the electronic communication between pyrrole and selenophene nuclei. Divergent syntheses of 2-(selenophen-2-yl)pyrroles and their N-vinyl derivatives from available 2-acylselenophenes and acetylenes in a one-pot procedure have been devised (see scheme), which provide access to these exotic heterocyclic ensembles.The divergent syntheses of 2-(selenophen-2-yl)pyrroles and their N-vinyl derivatives from available 2-acylselenophenes and acetylenes in a one-pot procedure make these exotic heterocyclic ensembles accessible. Now we face a potentially vast area for exploration with a great diversity of far-reaching consequences including conducting electrochromic polymers with repeating of pyrrole and selenophene units (emerging rivalry for polypyrroles and polyselenophenes), the synthesis of functionalized pyrrole-selenophene assembles for advanced materials, biochemistry and medicine, exciting models for theory of polymer conductivity.

The reaction of pyrrole-2-carbodithioates with methylenoactive nitriles and 2-benzoyl-1-bromoacetylene in the KOH-DMSO system leads to functionally substituted pyrrolothiazoles in 59-85% yield. [ABSTRACT FROM AUTHOR]

A topochemical reaction of pyrroles with bromotrifluoroacetylacetylene proceeds in solid Al 2 O 3 at room temperature in two different directions depending on the substituent character at the nitrogen atom. While N -vinylpyrroles undergo the cross-coupling to give N -vinyl-2-(trifluoroacetylethynyl)pyrroles in up to 58% yield, unsubstituted NH-pyrroles add to the triple bond to afford exclusively E-2-(1-bromo-2-trifluoroacetylethenyl)pyrroles in 12–21% yields. It has been shown ( 1 H NMR, quantum-chemical calculations) that the reaction is controlled by the strong intramolecular hydrogen bonding between NH and carbonyl groups. [ABSTRACT FROM AUTHOR]

Cross-coupling of NH-pyrroles with 1-bromo-2-(trifluoroacetyl) acetylene in the Al 2 O 3 medium affords ( E )-4-bromo-1,1,1-trifluoro-4-(pyrrol-2-yl)but-3-en-2-ones instead of the expected 2-ethynylated products. Quantum-chemical analysis shows strong intramolecular hydrogen bonding between NH and trifluoroacetyl groups, higher NH acidity and deeper charge transfer to the ethenyl moiety, which determines the reaction pathway. [ABSTRACT FROM AUTHOR]

Depending on the substituent character at the nitrogen atom, pyrroles react acetylene (II) in two different directions. [ABSTRACT FROM AUTHOR]