Diorganyl Dichalcogenides and Copper/Iron Salts: Versatile Cyclization System To Achieve Carbo- and Heterocycles from Alkynes

Abstract

Organochalcogen-containing cyclic molecules have shown several promising pharmacological properties. Consequently, different synthetic strategies have been developed to their obtaining in the last years. Particularly due to the low cost and environmental aspects, copper and iron-promoted cyclization reactions of alkynyl substrates have been broadly and efficiently applied to this purpose. In this way, this manuscript consists on an overview of the most recent advances in the synthesis of organochalcogen-containing carbo- and heterocycles by reacting diorganyl disulfides, diselenides and ditellurides with alkyne derivatives in the presence of copper and iron salts to promote cyclization reactions.

PhICl2-Mediated Regioselective and Electrophilic Oxythio/Selenocyanation of o-(1-Alkynyl)benzoates: Access to Biologically Active S/SeCN-Containing Isocoumarins

“…Then the reaction of thiocyanate with thiocyanogen chloride provides (SCN) 2 , which further reacts with the oxidative PhICl 2 to give thiocyanogen chloride ( Tao et al, 2021 ). Next, electrophilic addition between the reactive thiocyanogen chloride with substrate 1a gave rise to intermediate B ( Xing et al, 2019a ; An et al, 2020 ; Hellwig et al, 2020 ; Lynch and Scanlan, 2020 ; Sun et al, 2020 ; Jurinic et al, 2021 ; Slivka and Onysko, 2021 ). Due to the presence of the adjacent electron-withdrawing methoxycarbonyl group which makes the C (sp 2 ) connecting with the Ph substituent more electron-deficient, a favored intramolecular 6-exo cyclization occurred in intermediate B , leading to formation of the cyclic intermediate C .…”

Recent Approaches in Transition Metal-Catalyzed Chalcogenative Heteroannulation of Alkenes and Alkynes

“…In sum, the interesting properties presented by organochalcogen compounds offer wide research opportunities, considering the design of small molecules presenting pharmacological activity and toxicological safety to new materials. The heterocyclization of alkenes and alkynes by using halogen- [30][31][32][33] or chalcogenbased electrophiles [34,35], or under photocatalysis and electrochemistry conditions involving radical intermediates, has been well documented [36,37]. Traditionally, these cyclization reactions are conducted for alkenes and alkynes neighboring nucleophilic substituents at an appropriate position, which can limit the applicability as most of them are not readily available starting materials, owing to its obtaining of a transition-metal catalysis in at least one reaction step.…”