A transition-metal-free one-pot synthesis of 3-halo-2-organochalcogenylbenzo[b]chalcogenophenes has been developed using 1-(2-organochalcogenylethynyl)-2-butylchalcogenylbenzenes generated in situ from 1-(2,2-dibromovinyl)-2-organochalcogenylbenzenes and diorganoyl dichalcogenides. By this method, several 2,3-disubstituted benzo[b]chalcogenophenes were prepared in yields of 48-93%. The mechanistic investigation suggests that the formation of chalcogenoacetylenes containing an adjacent chalcogen atom in the first step of this one-pot procedure involves acetylide anions formed from 1-(2,2-dibromovinyl)-2-organochalcogenylbenzenes and mild bases.

We have developed an efficient chalcogenylation of electron-rich naphthalene derivatives catalyzed by FeCl3 and KI. The methodology provides access to several nonsymmetrical diorganoyl chalcogenides (S, Se) by selective C1 chalcogenylation of 2-naphthols or 2-naphthylamines using simple and cheap catalysts. Several control experiments supported the hypothesis that a redox reaction between Fe(III) and KI produces I2, which catalyzed the chalcogenylation.

We developed a combined experimental and theoretical study that gives mechanistic insights into the silver-catalyzed direct selanylation of indoles.

The structure of the title compounds 3-bromo-2-(phenylsulfanyl)benzo[b]thiophene (C14H9BrS2; 1), 3-iodo-2-(phenylsulfanyl)benzo[b]thiophene (C14H9IS2; 2), 3-bromo-2-(phenylselanyl)benzo[b]selenophene (C14H9BrSe2; 3), and 3-iodo-2-(phenylselanyl)benzo[b]selenophene (C14H9ISe2; 4) were determined by single-crystal X-ray diffraction; all structures presented monoclinic (P21/c) symmetry. The phenyl group is distant from the halogen atom to minimize the steric hindrance repulsion for all structures. Moreover, the structures of 3 and 4 show an almost linear alignment of halogen–selenium–carbon atoms arising from the intramolecular orbital interaction between a lone pair of electrons on the halogen atom and the antibonding σ*Se–C orbital (n halogen→σ*Se–C). This interaction leads to significant differences in the three-dimensional packing of the molecules, which are assembled through π–π and C—H...π interactions. These data provide a better comprehension of the intermolecular packing in benzo[b]chalcogenophenes, which is relevant for optoelectronic applications.