Access to 3-alkylselenindoles by multicomponent reaction of indoles, selenium powder and unactivated alkyl halides under transition-metal-free conditions

Visible-light induced selenocyclization of 2-ethynylanilines under ambient conditions: simple FeBr3 as a dual-functional catalyst

We report herein a visible-light induced, Fe-catalyzed selenocyclization of 2-ethynylanilines with diselenides under ambient conditions, employing ethyl acetate as a benign solvent with no stoichiometric additive required. The simple iron salt FeBr3 serves as both a photo-induced LMCT (Ligand-to-Metal Charge Transfer) catalyst and a Lewis acid catalyst to promote the desired transformation in a sustainable manner, enabling the facile synthesis of diverse 3-selenylindoles with extended substitution patterns. Moreover, gram-scale reactions and late-stage functionalization of bioactive molecules further highlight the synthetic practicality of this method.

Electrochemical selenocyclization of 2-ethynylanilines with diselenides: facile and efficient access to 3-selenylindoles

An efficient electrochemical selenocyclization strategy for the synthesis of 3-selenylindoles from 2-ethynylanilines and diselenides has been developed in simple tube- or beaker-type undivided cells under ambient conditions. Notably, these sustainable transformations are completed within a short time with low equivalents of charges, diselenides and electrolytes, exhibiting a broad substrate scope with excellent functional group compatibility. Moreover, a gram-scale electrosynthesis and late-stage functionalization of complex molecules further demonstrate the practical synthetic potential of this facile electrochemical system.

Copper borate (CuB4O7)-promoted multi-component green synthesis of 2,4,5-triarylimidazole derivatives and evidence of in situ conversion of copper borate (CuB4O7) into Cu(OAc)2 in the presence of NH4OAc

A green, efficient, and straightforward methodology for the three-component synthesis of 2,4,5-triarylimidazole has been developed under solvent-free conditions using unconventional CuB₄O₇ as a promoter. This green approach encouragingly provides access to a library of 2,4,5-tri-arylimidazole. Also, we have been able to isolate the compound (5) and (6) in situ, which provides an insight into the direct conversion of CuB₄O₇ into copper acetate in the presence of NH₄OAc under solvent-free condition. The main advantage of this protocol includes an easy reaction procedure, short reaction time, and easy work up of the product without using any tedious separation method.

CuBr2-Catalyzed Annulation of 2-Bromo-N-Arylbenzimidamide with Se/S8 Powder for the Synthesis of Benzo[d]isoselenazole and Benzo[d]isothiazole

A CuBr₂-catalyzed annulation of 2-bromo-N-arylbenzimidamide with selenium/sulfur powder for the synthesis of benzo[d]isoselenazole and benzo[d]isothiazole in generally good yields was investigated. This synthetic strategy features good substrate scope and functional group tolerance. Furthermore, the corresponding products could be converted into N-aryl indoles via rhodium^III-catalyzed ortho C-H activation of the N-phenyl ring, providing an efficient approach for axial aromatic molecules.

One-Pot Multicomponent Polymerization, Metal-, and Non-Metal-Catalyzed Synthesis of Organoselenium Compounds

The one-pot multicomponent synthetic strategy of organoselenium compounds represents an alternative and robust protocol to the conventional multistep methods. During the last decade, a potential advance has been made in this domain. This review discusses the latest advances in the polymerization, metal, and metal-free one-pot multicomponent synthesis of organoselenium compounds.