Catalytic Asymmetric\nC–H Activation/Cyclization\nof Sulfoximines with Sulfoxonium Ylides by a Chiral η<sup>6</sup>‑Benzene Ruthenium(II) Catalyst

Chiral η<sup>6</sup>-benzene\nruthenium(II) (BenRu<sup>II</sup>)-catalyzed asymmetric C–H\nactivations are challenging and\nrarely seen in the literature. Herein, the asymmetric C–H activation/cyclization\nof sulfoximines with sulfoxonium ylides catalyzed by the chiral BenRu<sup>II</sup> catalyst derived from (<i>S</i>)-H<sub>8</sub>–BINOL is described. It provides efficient access to various\nsulfur-chiral 1,2-benzothiazine 1-oxides in high yields with high\nenantioselectivities (up to 99% yield and 98% ee). Kinetic resolution\nof racemic sulfoximines was also feasible. The reaction mechanism\nwas studied by the tool of H/D exchange and the kinetic isotope effect.\nThe metallacycle revealing the origin of chiral induction was prepared,\ncharacterized, and proved effective for the model reaction. This work\ndemonstrates the great potential of chiral BenRu<sup>II</sup> catalysts\nfor asymmetric C–H activation.