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Herein, we report a reductive cross‐coupling reaction of α‐oxy halides, simply generated from aldehydes, with a series of C(sp2)‐ and C(sp)‐electrophiles. A wide range of aryl and heteroatom aryl halides, vinyl bromides, alkynyl bromides, and acyl chlorides react with unhindered and hindered aldehyde‐derived α‐oxy halides by providing protected alcohols as well as α‐hydroxy ketones. Noteworthy, the reductive couplings are achieved not only through thermal catalysis with the use of metal reductants but also by photocatalysis, electrochemistry, and mechanochemistry. The unrestricted interchange of the four strategies indicates their underlying mechanistic similarities. The generation of NiI intermediate is proposed to be the key point for ketyl radical formation via a single‐electron transfer (SET) event, which was rationalized by an array of control experiments and density functional theory (DFT) calculations. [ABSTRACT FROM AUTHOR]

Chemical transformations based on cascade reactions have the potential to simplify the preparation of diverse and architecturally complex molecules dramatically. Herein, we disclose an unprecedented and efficient method for the cross‐coupling of radical precursors, dienes, and electrophilic coupling partners via a photoredox‐ and nickel‐enabled cascade cross‐coupling process. The cascade reaction furnishes a diverse array of saturated carbo‐ and heterocyclic scaffolds, thus providing access to a quick gain in C−C bond saturation. [ABSTRACT FROM AUTHOR]