Computational methods are used to model the addition of electron deficient radicals (·CH₂CN or ·CF₃) at 2 or 3‐positon of indoles. Lower reaction barriers are found for the reaction at C2 rather than C3. The resulting C2‐substituted indole radical intermediate is also lower in energy leading to the experimentally observed C2 selectivity. This is in contrast to the long established C3 selectivity for indole reactions with electrophiles.

中文翻译：

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将缺电子自由基添加到吲哚的 C2 位置的选择性

计算方法用于模拟在吲哚的 2 位或 3 位添加缺电子自由基（· CH ₂ CN 或· CF ₃）。发现C2处的反应比C3处的反应势垒更低。所得的C2取代的吲哚自由基中间体的能量也较低，导致实验观察到的C2选择性。这与长期以来建立的吲哚与亲电子试剂反应的C3选择性形成对比。