Optimization and Gram-Scale Preparation of <i>S</i>‑Trifluoromethyl Sulfoximines and Sulfilimino Iminiums, Powerful Reagents for the Late Stage Introduction of the CF<sub>3</sub> Group BarthelemyAnne-Laure CertalVictor DagoussetGuillaume AnselmiElsa BertinLuc FabienLaurence SalguesBruno CourtesPhilippe PomaChristian El-AhmadYoussef MagnierEmmanuel 2019 <i>S</i>-Trifluoromethyl sulfoximines and <i>S</i>-trifluoromethyl sulfilimino iminiums are important reagents for the electrophilic or radical late-stage introduction of the CF<sub>3</sub> 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 <b>4</b> and 40 g of <i>S</i>-trifluoromethyl sulfilimino iminium <b>5</b> 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.