Late-stage fluorination reactions aim to reduce the synthetic limitations of conventional organofluorine chemistry with respect to substrate scope and functional group tolerance. C–F bond formation is commonly thermodynamically favorable but almost universally associated with high kinetic barriers. Apart from PhenoFluor chemistry, most modern aromatic fluorination methods reported to date rely on the use of transition metal catalysts, with C–F bonds often formed through reductive elimination. Reductive elimination chemistry to make C–X bonds becomes increasingly challenging when moving to higher atomic numbers in the periodic table from C–C to C–F, in part because of higher metal–X bond dissociation energies. The formation of C–C, C–N, and C–O bonds via reductive elimination has become routine in the 20th century, but it took until the 21st century to develop complexes that could afford general C–F bond formation. The availability of such complexes enabled the substrate scope of modern fluorination chemistry to exceed that of conventional fluorination.

中文翻译：

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通过PhenoFluor试剂介导的协同亲核芳香取代，容易形成CF键

后期氟化反应旨在减少常规有机氟化学在底物范围和官能团耐受性方面的合成限制。C-F键的形成通常在热力学上是有利的，但几乎都与高动力学障碍相关。除PhenoFluor化学外，迄今报道的大多数现代芳族氟化方法都依赖于过渡金属催化剂的使用，其中CF键通常通过还原消除形成。当从C C到C F过渡到更高的原子序数时，还原消除化学反应使C X键变得越来越具有挑战性，部分原因是由于较高的金属X键解离能。在20世纪，通过还原性消除形成C–C，C–N和C–O键已成为惯例，但是直到21世纪，人们才开发出可以形成一般CF键的络合物。此类络合物的可用性使得现代氟化化学的底物范围能够超过常规氟化的范围。