AbstractDearomative spirocyclization reactions represent a promising means to convert arenes into three‐dimensional architectures; however, controlling the regioselectivity of radical dearomatization with nonactivated arenes to afford the spirocyclizative 1,2‐difunctionalization other than its kinetically preferred 1,4‐difunctionalization is exceptionally challenging. Here we disclose a novel strategy for dearomative 1,2‐ or 1,4‐amidoximation of (hetero)arenes enabled by direct visible‐light‐induced homolysis of N−NO bonds of nitrosamides, giving rise to various highly regioselective amidoximated spirocycles that previously have been inaccessible or required elaborate synthetic efforts. The mechanism and origins of the observed regioselectivities were investigated by control experiments and density functional theory calculations.
摘要脱芳基螺环化反应是将烷烃转化为三维结构的一种很有前景的方法;然而,控制非活化烷烃脱芳基反应的区域选择性,以获得螺环化的 1,2-二官能度,而不是其动力学上偏好的 1,4-二官能度,却极具挑战性。在这里,我们揭示了一种新策略,即通过可见光直接诱导亚硝酰胺的 N-NO 键的均裂,实现(杂)烷的 1,2- 或 1,4- 氨基肟化,从而产生各种高区域选择性的氨基肟化螺环,而这些螺环以前是无法获得的,或者需要精心的合成工作。通过对照实验和密度泛函理论计算,研究了观察到的区域选择性的机理和起源。