Double cobalt-catalyzed atroposelective C–H activation: One-step synthesis of atropisomeric indoles bearing vicinal C–C and C–N diaxes

Expanding the borders of asymmetric synthesis by designing original chiral molecules and sustainable strategies to synthesize them holds great promise not only for the pharmaceutical industry but also for material science and agrochemistry. In particular, straightforward, one-step synthesis of enantiopure scaffolds featuring two proximal stereogenic axes presents a great scientific challenge. Herein, a unique asymmetric C–H activation reaction has been used to achieve the first intermolecular direct arylation-type reaction, affording indoles bearing simultaneous C2-atropisomeric Ar–Ar' axis and C–N axial chirality. Remarkably, the desired reactivity could be achieved using a chiral cobalt complex as a sustainable and cheap catalyst, thus delivering the expected multi-atropisomeric compounds in high yields and excellent diastereoselectivities and enantioselectivities. In addition, detailed mechanistic studies provide fundamental comprehension of this unique transformation.