A general arene C–H functionalization strategy via electron donor-acceptor complex photoactivation

The photoactivation of electron donor-acceptor (EDA) complexes has emerged as a sustainable, selective and versa-tile strategy for the generation of radical species. However, when it comes to aryl radical formation, this strategy remains hamstrung by the electronic properties of the aromatic radical precursors and electron-deficient aryl halide acceptors are required. This has prevented the implementation of a general synthetic platform for aryl radical for-mation. Our study introduces triarylsulfonium salts as acceptors in photoactive EDA-complexes, used in combina-tion with catalytic amounts of newly-designed amine donors. The sulfonium salt label renders inconsequential the electronic features of the aryl radical precursor and, more importantly, it is installed regioselectively in native aro-matic compounds by C–H sulfenylation. Using this general, site-selective aromatic C–H functionalization approach, we have developed metal-free protocols for the alkylation and cyanation of arenes, and showcased their application in both the synthesis and the late-stage modification of pharmaceuticals and agrochemicals.

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.

Formal [4 + 1] annulation of fluorinated sulfonium salt with cyclic unsaturated imines to access CF3-substituted pyrroles

A structurally diverse set of CF3-substituted pyrroles was efficiently constructed in acceptable to excellent yields.