Copper/Palladium-Catalyzed Cyclization/Cross-Coupling Cascade Reaction of 2- gem -Dibromovinyl Aryl Selenides: Synthesis of 2-Substituted Benzo[ b ]selenophenes

Straightforward synthesis of N-arylindoles via one-pot Fischer indolisation-indole N-arylation

A microwave-promoted, one-pot, three-component synthesis of N-arylindoles has been developed, utilising sequential Fischer indolisation then copper(i)-catalysed indole N-arylation. Novel arylation conditions were identified that use a simple and cheap catalyst/base system (Cu₂O/K₃PO₄) in an environmentally benign solvent (ethanol), with no requirement for ligands, additives or exclusion of air or water, and microwave irradiation enabled significant acceleration of this commonly sluggish process. These conditions were designed to dovetail with Fischer indolisation, and the resulting one-pot, two-step sequence is rapid (total reaction time = 40 minutes), operationally straightforward, generally high yielding and it draws upon readily available hydrazine, ketone/aldehyde and aryl iodide building blocks. This process shows broad substrate tolerance and we have demonstrated its utility in the synthesis of 18 N-arylindoles bearing varied and useful functionality.

Photoinduced Construction of Thieno[3,4-c]quinolin-4(5H)-ones/Selenopheno[3,4-c]quinolin-4(5H)-ones Using Diphenyl Disulfide or Diphenyl Diselenide as Sulfur or Selenium Sources

A photocatalytic synthesis of thieno[3,4-c]quinolin-4(5H)-ones/selenopheno[3,4-c]quinolin-4(5H)-ones using diphenyl disulfide or diphenyl diselenide as sulfur or selenium sources was developed. Two C-S/Se bonds and one C-C bond were constructed simultaneously without transition metals and other additives.

Synthesis of selenated tetracyclic indoloazulenes via iodine and diorganyl diselenides

Herein, we report an efficient protocol for the synthesis of selenated tetracyclic indoloazulenes. The reaction of diorganyl diselenides with molecular iodine in dichloromethane leads to the in situ formation of organo selenenyl iodide. The synthesis of selenylated tetracyclic indoloazulenes through intramolecular cascade cyclization has been achieved via organo selenenyl iodide and bisindole at room temperature under metal-free conditions in good yields. All compounds were fully characterized by the FT-IR, HRMS, and ¹H, ¹³C and ⁷⁷Se NMR spectral data.

Recent Advances in the Synthesis of Selenophenes and Their Derivatives

The selenophene derivatives are an important class of selenium-based heterocyclics. These compounds play an important role in prospecting new drugs, as well as in the development of new light-emitting materials. During the last years, several methods have been emerging to access the selenophene scaffold, employing a diversity of cyclization-based synthetic strategies, involving specific reaction partners and particularities. This review presents a comprehensive discussion on the recent advances in the synthesis of selenophene-based compounds, starting from different precursors, highlighting the main differences, the advantages, and limitations among them.

Synthesis and photophysical properties of selenopheno[2,3-b]quinoxaline and selenopheno[2,3-b]pyrazine heteroacenes

In this paper, we report the novel synthesis of three different heterocycles, namely 2-arylselenopheno[2,3-b]quinoxaline, 3-(aryl/alkylselanyl)-2-arylselenopheno[2,3-b]quinoxaline and 6-phenyl-7-(arylselanyl)selenopheno[2,3-b]pyrazine derivatives, from the corresponding 2,3-dichloroquinoxaline and 2,3-dichloropyrazine derivatives. Furthermore, photophysical properties were investigated to study the effect of heteroatoms on UV-absorbance and fluorescence properties.

In situ air oxidation and photophysical studies of isoquinoline-fused N-heteroacenes

An efficient, metal free and environment friendly synthesis of isoquinoline-fused benzimidazole has been developed via in situ air oxidation. Also, syntheses of isoquinoline-fused quinazolinone heteroacenes were successfully achieved. The synthesized isoquinoline-fused benzimidazole and isoquinoline-fused quinazolinone derivatives showed λmax, Fmax and Φf values in the ranges 356-394 nm, 403-444 nm and 0.063-0.471, respectively, in CHCl3.

A Three-Component Strategy for Benzoselenophene Synthesis under Metal-Free Conditions Using Selenium Powder

An efficient three-component benzoselenophenes formation has been developed from substituted indoles, acetophenones, and selenium powder under metal-free conditions. 2-Aryl indoles played an important role to promote benzoselenophene formation from acetophenone derivatives and selenium powder. One C-C and two C-Se bonds were selectively formed to provide 40 new benzoselenophenes in good yields.