Asymmetric Synthesis of Spirocyclic Sultams via Nickel-Catalyzed Arylative Cyclization

A versatile synthesis of chiral spirocyclic sultams with a tunable ring size via nickel-catalyzed asymmetric anti-arylative cyclization of alkyne-tethered N-sulfonyl ketimines with arylboronic acids has been reported. This protocol exhibits exceptional efficiency, providing a broad array of chiral [5,6]-spirocyclic and [5,5]-spirocyclic sultams with excellent yields and enantioselectivities (up to 98% yield and 99% ee). The applicability of this strategy is further accentuated by the gram-scale synthesis and diverse transformations.