Cleavage of carbon-carbon bonds remains a challenging task in organic synthesis. Traditional methods for splitting C_sp2=C_sp2 bonds into two halves typically involve non-redox (metathesis) or oxidative (ozonolysis) mechanisms, limiting their synthetic potential. Disproportionative deconstruction of alkenes, which yields one reduced and one oxidized fragment, remains an unexplored area. In this study, we introduce a redox-neutral approach for deleting a C_sp2 carbon unit from substituted arylalkenes, resulting in the formation of an arene (reduction) and a carbonyl product (oxidation). This transformation is believed to proceed through a mechanistic sequence involving visible-light-promoted anti-Markovnikov hydration, followed by photoredox cleavage of C_sp3-C_sp3 bond in the alcohol intermediate. A crucial consideration in this design is addressing the compatibility between the highly reactive oxy radical species in the latter step and the required hydrogen-atom-transfer (HAT) reagent for both steps. We found that ethyl thioglycolate serves as the optimal hydrogen-atom shuttle, offering remarkable chemoselectivity among multiple potential HAT events in this transformation. By using D₂O, we successfully prepared dideuteromethylated (-CD₂H) arenes with good heavy atom enrichment. This work presents a redox-neutral alternative for alkene deconstruction, with considerable potential in late-stage modification of complex molecules.

碳-碳键的断裂仍然是有机合成中的一项具有挑战性的任务。将 C _sp2 =C _sp2键分裂成两半的传统方法通常涉及非氧化还原（复分解）或氧化（臭氧分解）机制，限制了它们的合成潜力。烯烃的歧化解构产生一种还原片段和一种氧化片段，仍然是一个未开发的领域。在本研究中，我们引入了一种氧化还原中性方法，用于从取代的芳基烯烃中删除 C _sp2碳单元，从而形成芳烃（还原）和羰基产物（氧化）。这种转化被认为是通过一个机械序列进行的，涉及可见光促进的抗马尔可夫尼科夫水合，然后是醇中间体中 C _sp3 -C _sp3键的光氧化还原裂解。该设计中的一个关键考虑因素是解决后一步中的高反应性氧自由基物质与这两个步骤所需的氢原子转移（HAT）试剂之间的兼容性。我们发现，巯基乙酸乙酯充当最佳的氢原子穿梭，在该转化中的多个潜在 HAT 事件中提供了显着的化学选择性。利用D ₂ O，我们成功制备了具有良好重原子富集性的双氘甲基化(-CD ₂ H)芳烃。这项工作为烯烃解构提供了一种氧化还原中性的替代方案，在复杂分子的后期修饰方面具有相当大的潜力。