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Cation‐binding salen nickel catalysts were developed for the enantioselective alkynylation of trifluoromethyl ketones in high yield (up to 99 %) and high enantioselectivity (up to 97 % ee). The reaction proceeds with substoichiometric quantities of base (10–20 mol % KOt‐Bu) and open to air. In the case of trifluoromethyl vinyl ketones, excellent chemo‐selectivity was observed, generating 1,2‐addition products exclusively over 1,4‐addition products. UV‐vis analysis revealed the pendant oligo‐ether group of the catalyst strongly binds to the potassium cation (K+) with 1:1 binding stoichiometry (Ka=6.6×105 m−1). [ABSTRACT FROM AUTHOR]

Metal‐free, visible‐light‐induced site‐selective heteroarylation of remote C(sp3)−H bonds has been accomplished through the design of N‐alkoxyheteroarenium salts serving as both alkoxy radical precursors and heteroaryl sources. The transient alkoxy radical can be generated by the single‐electron reduction of an N‐alkoxypyridinium substrate by a photoexcited quinolinone catalyst. Subsequent radical translocation of the alkoxy radical forms a nucleophilic alkyl radical intermediate, which undergoes addition to the substrate to achieve remote C(sp3)−H heteroarylation. This cascade strategy provides a powerful platform for remote C(sp3)−H heteroarylation in a controllable and selective manner and is well suited for late‐stage functionalization of complex bioactive molecules. Remote access: Metal‐free, visible‐light‐induced site‐selective heteroarylation of remote C(sp3)−H bonds has been accomplished through the design of a class of N‐alkoxyheteroarenium salts serving as both alkoxy radical precursors and heteroaryl sources. This strategy features a photoredox radical cascade process involving the sequential fragmentation of an N‐alkoxyheteroarenium substrate, 1,5‐HAT reaction, and pyridylation, and is well suited for late‐stage functionalization of complex bioactive molecules. [ABSTRACT FROM AUTHOR]