The construction of C(sp3)−N bonds via direct N-centered radical addition with olefins under benign conditions is a desirable but challenging strategy. Herein, we describe an organo-photocatalytic approach to achieve anti-Markovnikov alkene hydroamidation with sulfonyl azides in a highly efficient manner under transition-metal-free and mild conditions. A broad range of substrates, including both activated and unactivated alkenes, are suitable for this protocol, providing a convenient and practical method to construct sulfonylamide derivatives. A synergistic experimental and computational mechanistic study suggests that the additive, Hantzsch ester (HE), might undergo a triplet-triplet energy transfer manner to achieve photosensitization by the organo-photocatalyst under visible light irradiation. Next, the resulted triplet excited state 3HE* could lead to a homolytic cleavage of C4−H bond, which triggers a straightforward H-atom transfer (HAT) style in converting sulfonyl azide to the corresponding key amidyl radical. Subsequently, radical addition of the amidyl radical to alkenes followed by HAT from p-toluenethiol could proceed to afford the desired anti-Markovnikov hydroamidation product. It is worth noting that mechanistic pathway bifurcation could be possible for this reaction. A feasible radical chain propagation mechanistic pathway is also proposed to rationalize the high efficiency of this reaction.

中文翻译：

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烯烃与磺酰叠氮化物的有机光催化反马尔可夫尼科夫氢酰胺化：实验和计算相结合的研究

在良性条件下通过与烯烃直接以 N 为中心的自由基加成来构建 C(sp3)−N 键是一种理想但具有挑战性的策略。在此，我们描述了一种有机光催化方法，在无过渡金属和温和的条件下以高效的方式实现与磺酰叠氮化物的反马尔可夫尼科夫烯烃氢酰胺化。多种底物，包括活化和未活化的烯烃，都适用于该方案，为构建磺酰胺衍生物提供了一种方便实用的方法。协同实验和计算机制研究表明，添加剂Hantzsch酯（HE）可能在可见光照射下通过三重态-三重态能量转移方式实现有机光催化剂的光敏化。接下来，产生的三重激发态 3HE* 可能导致 C4−H 键的均裂，从而触发直接的氢原子转移 (HAT) 方式，将磺酰叠氮转化为相应的关键酰胺自由基。随后，将酰胺基自由基加成到烯烃上，然后用对甲苯硫醇进行 HAT 加成，可以得到所需的抗马尔可夫尼科夫氢酰胺化产物。值得注意的是，该反应可能存在机械途径分歧。还提出了一种可行的自由基链增长机制途径，以合理化该反应的高效率。