Investigations into the selectivity of intermolecular alkyl radical additions to C–O- vs. C–C-double bonds in α,β-unsaturated carbonyl compounds are described. Therefore, a photoredox-initiated radical chain reaction is explored, where the activation of the carbonyl-group through an in situ generated Lewis acid – originating from the substrate – enables the formation of either C–O or the C–C-addition products. α,β-Unsaturated aldehydes form selectively 1,2-, while esters and ketones form the corresponding 1,4-addition products exclusively. Computational studies lead to reason that this chemo- and regioselectivity is determined by the consecutive step, i.e. an electron transfer, after reversible radical addition, which eventually propagates the radical chain.

中文翻译：

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链的传播决定了烷基对C–O和CC–C双键的化学选择性和区域选择性

描述了对α，β-不饱和羰基化合物中的C-O-与CC-双键的分子间烷基加成的选择性的研究。因此，探索了光氧化还原引发的自由基链反应，其中通过原位产生的路易斯酸（源自底物）活化羰基基团，可以形成C–O或C–C加成产物。α，β-不饱和醛选择性地形成1,2-，而酯和酮仅形成相应的1,4-加成产物。计算研究导致这种化学和区域选择性是由连续步骤确定的，即在可逆自由基添加后电子转移，该电子转移最终会扩散自由基链。