Visible-Light-Promoted Nickel-Catalyzed Cross-Coupling of Iodocarboranes with (Hetero)Arenes via Boron-Centered Carboranyl Radicals

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作   者：

Li, Shimeng;  Xie, Zuowei; 

作者机构：

Chinese Univ Hong Kong; 

关键词：

MEDICINAL CHEMISTRY;  TRANSITION;  FACILE SYNTHESIS;  UNIQUE PHARMACOPHORES;  CARBENE-BORYL RADICALS;  CLUSTERS;  PHOTOREDOX;  DRUG DISCOVERY;  BONDS;  B-C; 

期刊名称：

Journal of the American Chemical Society

i s s n：

0002-7863

年卷期：

2022 年 144 卷 18 期

页   码：

7960-7965

页   码：

摘   要：

A general strategy for the generation of hypervalent boron-centered carboranyl radicals at the B(3), B(4), and B(9) positions has been developed for the first time via visible-light-promoted iodine atom abstraction from iodo-o-carboranes by low-valent nickel complex. These radicals react with various (hetero)arenes to afford a wide range of cage B-arylated carborane derivatives at room temperature in very good to excellent yields with a broad substrate scope. Their electrophilicities are dependent on the vertex charges of the cage and follow the order B(3) > B(4) > B(9). Both visible light and nickel catalyst are proved critical to the generation of boron-centered carboranyl radicals. The involvement of boron radicals is supported by control experiments. A reaction mechanism associated with these reactions is also proposed. This strategy offers a new protocol for the generation of boron-centered carboranyl radicals at the selected boron vertex, leading to a facile synthesis of a large class of cage boron substituted carborane molecules.