Nickel-Catalyzed Reductive Cross-Coupling of Benzylic Sulfonium Salts with Aryl Iodides

A nickel-catalyzed cross-electrophile coupling of benzylic sulfonium salts with aryl iodides has been developed, providing direct access to diarylalkanes from readily available and stable coupling partners. Preliminary mechanistic studies suggest that the C–S bond cleavage proceeds through a single-electron transfer process to generate a benzylic radical.

Application of α-Amino Radicals as the Reaction Activators

α-Aminoalkyl radicals are easily accessible through multiple pathways from various precursors. Apart from their utilization as N-containing building blocks, they have recently been used as halogen atom abstraction reagents or single-electron reductants to transform organic halides or sulfonium salts to their corresponding highly reactive radical species. Benefiting from the richness of various halides and the diverse reactivity of radical intermediates, new transformations of halides and sulfonium salts have been developed. This short review summarizes this emerging chemistry that uses α-amino radicals as the reaction activators.

Recent Advances on Annulation Reactions with Allyl and Propargyl Sulfonium Salts

Allyl and propargyl sulfonium salts are readily available reagents and have recently emerged as versatile building blocks in the assembly of cyclic skeletons. As an alternative to the classical sulfonium salts, allyl and propargyl sulfonium salts can convert to the corresponding vinyl sulfur ylide or allenic sulfonium salt intermediates that contain diverse nucleophilic or electrophilic reactive positions, thereby enabling a great variety of annulation reactions. In this review, we provide a comprehensive overview of the recent developments on this growing field by summarizing the annulation reactions involving allyl and propargyl sulfonium salts.