The C–F bond is recognized as the strongest single bond in organic chemistry. Activating such inert bonds typically demands rigorous reaction conditions, often involving expensive transition metal catalysts or harsh reagents. In stark contrast, this study demonstrates reagent-free defluorosubstitution reactions using only water. We observed the selective cleavage of Csp²–F and Csp³–F bonds, resulting in the formation of highly reactive carbocation species and fluoride anions at the air–water interface when aqueous solutions of organofluorine substrates (ArF and ArCF₃) were sprayed into the air. The carbocations formed at the interface subsequently reacted with various nucleophiles to yield defluorosubstitution products. A mechanistic investigation suggests that a one-electron reduction of the aromatic substrate facilitates rapid heterolytic cleavage of the C–F bond, occurring in less than a millisecond. Thus, fluorine, often described as a “small atom with a big ego”, has been effectively knocked out of organofluorine compounds by water.

中文翻译：

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水打破最强的有机键：微滴气-水界面的脱氟取代

C-F 键被认为是有机化学中最强的单键。激活这种惰性键通常需要严格的反应条件，通常涉及昂贵的过渡金属催化剂或苛刻的试剂。与此形成鲜明对比的是，本研究展示了仅使用水的无试剂脱氟取代反应。我们观察到 Csp^2-F 和 Csp^3-F 键的选择性裂解，当有机氟底物 （ArF 和 ArCF₃） 的水溶液喷洒到空气中时，导致在空气-水界面处形成高反应性碳阳离子和氟化物阴离子。在界面处形成的碳阳离子随后与各种亲核试剂反应，产生脱氟取代产物。机理研究表明，芳香族底物的单电子还原促进了 C-F 键的快速异质裂解，发生在不到一毫秒的时间内。因此，氟，通常被描述为“大自我的小原子”，已经被水有效地从有机氟化合物中敲除出来。