Construction of Axially Chiral Biaryls via Atroposelective ortho-C–H Arylation of Aryl Iodides

This is the authors' abstract. We don't add key points for this paper.

Due to the dichotomy between reactivity and stereoselectivity, the synthesis of axially chiral biaryls via enantioselective C–H arylation remains a daunting challenge. This full account describes the development of a general and modular platform for the construction of axial chirality through atroposelective ortho -C–H arylation of aryl iodides based on palladium/chiral norbornene cooperative catalysis. It is a three-component cascade process that involves readily available aryl iodides, 2,6-substituted aryl bromides, and various terminating reagents (e.g., olefins, alkynes, boronic acids, etc.) as building blocks. Key features of this method include broad functional group tolerance, high enantioselectivities, a distinct stereoinduction model, and good step economy and scalability. Notably, this method is also amenable for the synthesis of phenanthridinones with C–N axial chirality and chiral fluorenols through axial-to-axial and axial-to-central chirality transfer, respectively. Lastly, the origin of enantioselectivity in this method and the ortho -substituent effect of 2,6-substituted aryl bromides on stereoinduction are elucidated by density functional theory calculations.