An important challenge in the Cα-heteroarylation of ethers is the requirement of a large excess amount of ethers (that are used as solvents in many cases) to achieve effective transformations. This drawback has significantly restricted the Cα-heteroarylation of ethers to the use of simple and easily accessible ether substrates. To overcome this limitation, a new, efficient, N-hydroxysuccinimide (NHS) mediated, mild and metal-free CDC strategy for the direct Cα-heteroarylation of diverse ethers has been developed. Different to our previous benzaldehyde mediated photoredox Cα-heteroarylation, we have identified NHS as a new and efficient mediator without using light. A distinct non-photoredox engaged hydrogen-atom-transfer (HAT) mechanism that used a nitrogen-centered radical cation produced from NHS is initially revealed. Notably, only 5–10 equivalents of ethers as coupling partners are used, which allows for structurally diverse and complex ethers to engage in this process, to create highly medicinally relevant Cα-heteroarylated ethers. Furthermore, more structurally diverse heterocyclics can serve as reactants for this process.

The efficient and selective C–H silylation of heteroarenes, especially the pharmaceutically relevant electron-deficient heteroarenes, represents a great challenge in organic synthesis. Herein we wish to report a distinctive visible light-promoted photocatalytic C–H silylation approach that enables the direct coupling of trialkylhydrosilanes with both electron-deficient and -rich heteroarenes as well as with cyano-substituted arenes in moderate to high yields and with good regioselectivity. The protocol features operational simplicity, mild reaction conditions, and the use of safe and readily available Na₂S₂O₈, bis(trimethylsilyl) peroxide (BTMSPO) or ⁱPr₃SiSH as the radical initiators. Notably, the challenging bulky and inert trialkylhydrosilanes, such as (t-butyldimethyl)silane (^tBuMe₂SiH) and (triisopropyl)silane (ⁱPr₃SiH), work smoothly with the protocol. Moreover, despite the higher stability of ^tBuMe₂Si silylation products, our studies revealed their great reactivity and versatility in diverse C–Si-based chemical transformations, providing an operationally simple, low-cost, and environmentally benign synthetic technology for molecule construction and elaboration.

A photoredox/nickel dual-catalyzed decarboxylative cross-coupling reaction of anomeric ribosyl/deoxyribosyl acids with aryl/heteroaryl bromides has been developed. The reaction proceeds smoothly under visible-light irradiation and features the using of cost-effective and easily handled catalysts and starting materials, which allows the highly stereoselective synthesis of diverse aryl/heteroaryl-C-nucleosides in moderate to high yields.

Benzylic C–H alkoxylation via C–H/O–H cross-coupling represents an attractive strategy to access highly functionalized benzylic ethers but remains challenging due to the difficulty in improving the efficiency and selectivity. Herein we wish to report a highly efficient photoredox/nickel dual-catalytic strategy for the site-selective and chemoselective benzylic C–H alkoxylation using readily available Selectfluor as the oxidant. The protocol features broad substrate scope and excellent functional group compatibility and allows the transformation of various of alcohols to pharmaceutically relevant benzylic ethers in moderate to excellent yields under mild reaction conditions. CD₃OD was well tolerated, providing a useful synthetic tool for the synthesis of valuable deuterated pharmaceutical molecules. This method is also highlighted by the late-stage introduction of valuable alkoxy groups into pharmaceutical molecules and the structure modification of saccharides.