Regioselective Dearomative Amidoximation of Nonactivated Arenes Enabled by Photohomolytic Cleavage of N-nitrosamides
Pan-Feng Yuan1, Xie-Tian Huang1, Linhong Long2
1State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou, 730000, China.
Abstract:
Dearomative 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.
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