Enantioselective Synthesis of Chiral‐at‐Sulfur 1,2‐Benzothiazines by CpxRhIII‐Catalyzed C−H Functionalization of Sulfoximines

Abstract Sulfoximines with stereogenic sulfur atoms are attractive structural motifs in drug discovery. A direct catalytic enantioselective method for the synthesis of sulfur‐chiral 1,2‐benzothiazines from readily accessible diaryl sulfoximines is presented. Rhodium(III) complexes equipped with chiral cyclopentadienyl ligands and paired with suitable carboxylic acid additives engage in an enantiodetermining C−H activation directed by the sulfoximine group. Subsequent trapping of the rhodacycle with a broad range of diazoketones gives access to S‐chiral 1,2‐benzothiazines with synthetically highly attractive substitution patterns in good yields and enantioselectivities.