Rhodium‐Catalyzed C−H Activation‐Based Construction of Axially and Centrally Chiral Indenes through Two Discrete Insertions

Abstract Reported herein is asymmetric [3+2] annulation of arylnitrones with different classes of alkynes catalyzed by chiral rhodium(III) complexes, with the nitrone acting as an electrophilic directing group. Three classes of chiral indenes/indenones have been effectively constructed, depending on the nature of the substrates. The coupling system features mild reaction conditions, excellent enantioselectivity, and high atom‐economy. In particular, the coupling of N ‐benzylnitrones and different classes of sterically hindered alkynes afforded C−C or C−N atropochiral pentatomic biaryls with a C‐centered point‐chirality in excellent enantio‐ and diastereoselectivity (45 examples, average 95.6 % ee ). These chiral center and axis are disposed in a distal fashion and they are constructed via two distinct migratory insertions that are stereo‐determining and are under catalyst control.