Synthesis of Axially Chiral C-N Scaffolds via Asymmetric Coupling with Enantiopure Sulfinyl Iodanes

Axially chiral C-N compounds are an emerging but scarcely investigated class of stereogenic molecules with potential applications as biologically active scaffolds and chiral ligands. The synthesis of these compounds is extremely challenging, and in particular, no metal-catalyzed asymmetric, intermolecular C-N coupling has been previously reported. Herein we disclose an intermolecular atropselective C-N coupling, occurring with excellent stereoselectivity. This Cu-catalyzed transformation is based on the use of highly active coupling partners (i.e., chiral iodanes bearing a very cheap and traceless sulfoxide auxiliary). Use of such original ortho-sulfoxide iodanes enables this unprecedented coupling to occur at room temperature, guaranteeing high atropselectivity and atropselectivity of the coupling products under reaction conditions. Because of extensive possible postmodifications of the optically pure products, a panel of C-N axially chiral scaffolds can now be accessed.