Acyl radicals are invaluable intermediates in organic synthesis, however their generation remains challenging. Herein, we present an unprecedented light‐driven, cobalt‐catalysed method for the generation of acyl radicals from readily available 2‐S‐pyridyl thioesters. The synthetic potential of this methodology was demonstrated in the Giese‐type acylation of activated olefins in the presence of heptamethyl cobyrrinate. This vitamin B₁₂ derivative proved to be the most efficient catalyst in the studied process. The developed method features broad substrate scope (38 examples), good functional group tolerance, and mild reaction conditions. Moreover, it is easily scalable (illustrated on a 20‐fold scale‐up procedure), enabling its preparative use. Mechanistic studies revealed that the reaction proceeds via a radical pathway with the key steps involving the formation of an acyl‐vitamin B₁₂ complex and subsequent photolysis of the Co−C bond.

中文翻译：

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光驱动的维生素B12催化的2-S-吡啶基硫代酯的酰基自由基生成

酰基是有机合成中不可估量的中间体，但是它们的产生仍然具有挑战性。本文中，我们提出了一种空前的光驱动，钴催化的方法，用于从易于获得的2- S-吡啶基硫代酯中生成酰基自由基。该方法的合成潜力已在庚二酸七甲酯存在下活化烯烃的Giese型酰化反应中得到了证明。这种维生素B ₁₂衍生物被证明是研究过程中最有效的催化剂。所开发的方法具有广泛的底物范围（38个示例），良好的官能团耐受性和温和的反应条件。此外，它易于扩展（在20倍的放大过程中进行了说明），从而可以进行准备性使用。机理研究表明，该反应通过自由基途径进行，关键步骤涉及酰基维生素B ₁₂络合物的形成以及随后的Co-C键光解。