Synthesis of CF₃-Containing Sulfur Heterocycles. The First Stable 2-Thietanol Derivative

The reaction of α,β-unsaturated CF₃-containing ketones R¹R²CCHCOCF₃ 1−4 with ammonium hydrosulfide was investigated. The structure of the enones was shown to influence the reaction path, and the corresponding six-membered sulfur heterocycles bearing trifluoromethyl groups, 5−8, or mercaptan, 9, were obtained. The reaction of 3-adamantylidene-1,1,1-trifluoropropan-2-one, 3, results in the corresponding four-membered heterocycle 8, which has a stable 2-thietanol fragment. The oxidation of sulfides 5−8 by hydrogen peroxide yields sulfones 10−12 or 1,3-sultine 13 (in the case of 8). Product stereochemistry and reaction mechanism are discussed.