Recent advances in selective mono-/dichalcogenation and exclusive dichalcogenation of C(sp²)–H and C(sp³)–H bonds

Abstract

Organochalcogen compounds are prevalent in numerous natural products, pharmaceuticals, agrochemicals, polymers, biological molecules and synthetic intermediates. Direct chalcogenation of C–H bonds has evolved as a step- and atom-economical method for...

I2 or I2/PIFA one-pot induced system for rapid synthesis of chalcogenated enamides, uracils or 2-pyridones under mild conditions

“…A survey of the literature revealed the successful use of hypervalent iodine( iii )-based reagents in synthesizing N -substituted indole derivatives through PIFA or PIDA reactions from amides or styrene-derived enamides. 22–24 Inspired by these findings, we surmised that the endo -enamide 1a–d type might undergo reaction with PIFA, resulting in the formation of the corresponding 2-pyridone chalcogenide 4 , representing its oxidized form. Therefore, 1a was subjected to the aforementioned chalcogenylation conditions with 1.2 equiv.…”

Visible-light-driven PCy3-promoted deselenization of 1,2-diselenides

“…Moreover, the unique electronic properties of selenium make this element indispensable in organic materials such as high-performance organic semiconductors for field-effect transistors 13–16 and thin film transistors. 17 Therefore, the development of an efficient method 18–20,41–61 for the construction of the C–Se bond has received continuous attention recently in organochalcogenide chemistry.…”

“…On the one hand, diselenides are more readily available than monoselenides. 41–49 On the other hand, most of the established methods for the synthesis of monoselenides are more or less inevitably accompanied by the formation of diselenides that are difficult to remove from the mixture due to their similar polarity to monoselenides (Fig. 2C).…”

Aminoselenation and Dehydroaromatization of Cyclohexanones with Anilines and Diselenides

“…Therefore, the choice of a suitable reaction system to avoid the dehydroaromatization of α-seleno cyclohexanones and promote their condensation with anilines is crucial for determining the success of cyclohexanone difunctionalization. Additionally, challenges are inevitably confronted with several side reactions, such as dehydrogenative homocoupling of anilines, dehydroaromatization of cyclic ketones with anilines, overselenation of aminoselenative products with diselenides, para-selenation of anilines with diselenides, and dehydrogenative diamination of cyclohexanones with anilines . It is noteworthy that the current deoxygenative difunctionalization of cyclic ketones not only addresses the frequently encountered region- and chemo-selectivity in arenes chemistry but also provides a conceptual new protocol for the preparation of polyfunctional arenes.…”