Optimization and Gram-Scale Preparation of S‑Trifluoromethyl Sulfoximines and Sulfilimino Iminiums, Powerful Reagents for the Late Stage Introduction of the CF₃ Group

S-Trifluoromethyl sulfoximines and S-trifluoromethyl sulfilimino iminiums are important reagents for the electrophilic or radical late-stage introduction of the CF₃ group. We disclose in this article a reappraisal of our previous methodologies and their adaptation to a large scale. More than 30 g of the key sulfoximine 4 and 40 g of S-trifluoromethyl sulfilimino iminium 5 are prepared without purification. DSC measurements have been performed on both the crude mixtures and the isolated compounds in order to ensure a safe process. The costs of the syntheses are also detailed and discussed.