The benzylic positions in drugs are sites that readily react with cytochrome P450 oxidases via single-electron oxidation. New synthetic methodologies to incorporate a fluoroalkyl group at the benzylic site are continually being developed, and in this paper, we report a metal-free and site-selective organophotoredox-catalyzed trifluoromethylthiolation of benzylic C-H bonds for a wide variety of alkyl arenes and heteroarenes. The precise and predictive regioselectivity among various C(sp3)-H bonds originates from an inner-sphere benzylic radical initiation mechanism, and avoids the use of external oxidants or hydrogen atom abstractors. Its practicality stems from the trifluoromethylthiolation of a series of drugs and complex organic molecules, which is overwhelmingly selective for benzyl groups. This operationally simple protocol can provide a general and practical access to structurally diverse benzylic trifluoromethyl sulfides produced from ubiquitous benzylic C-H bonds. Large scale trifluoromethylthiolation can be achieved with continuous flow photoredox technology.

The synthesis of valuable alkyl-substituted heteroarenes from abundant and inexpensive feedstocks under mild conditions is attractive and highly desirable in pharmaceutical and natural product synthesis. Minisci-type cross dehydrogenative coupling between heteroarenes and C­(sp3)–H bonds offers direct access to these important scaffolds in a step-economic manner. Herein, assisted by stop-flow microtubing reactors, an operationally simple protocol for the visible light-induced hydrogen-evolution cross coupling of heteroarenes with unactivated C­(sp3)–H bonds was developed in a metal- and external oxidant-free manner. A wide range of alkylated heteroarenes was generated with common feedstock chemicals, including ethane. Mechanistic studies indicated that photoredox-induced hydrogen atom transfer processes followed by dehydrogenative rearomatization delivered the desired coupling products. The merits of this strategy were further demonstrated by the late-stage functionalization of various complex bioactive molecules.

In this paper, visible-light-induced deoxyalkynylation of activated tertiary alcohols has been successfully performed under mild reaction conditions with ethynylbenziodoxole as the readily available alkynylation reagent. The desired C(sp 3 )−C(sp) coupling can smoothly occur with 4-CzIPN as a photocatalyst, affording a wide range of valuable alkynylation products bearing quaternary carbon centers in 37−84% yields.

Carbon‐based gas molecules are readily available feedstocks and are widely used in industry as building blocks or fuels. However, their application in the synthesis of fine chemicals has been hampered due to operational complexity, poor reaction efficiency and selectivity. Recent development of photoredox‐promoted transformations using such gaseous reagents has received considerable attention from the synthetic community. In this review, efforts in developing light‐promoted organic transformations using carbon‐based natural gases as C1 or C2 feedstocks and to overcome the associated challenges are briefly summarized.

The dehydrogenative cross-coupling (CDC) reaction of diversely substituted azoles was realized by copper and cobalt co-catalysis under air conditions.