Catalytic addition of trihalogenomethanesulfenyl chlorides to olefinic compounds

Direct Trifluoromethylthiolation Reactions: The “Renaissance” of an Old Concept

“…For example, the addition of CF 3 SCl to olefins can also occur without X‐ray or UV irradiation 19–21. Among the few alkenes evaluated (1‐hexene, cyclohexene, allyl bromide, vinyl bromide), it was found that the reaction rate increased in the case of olefins bearing electron‐donating substituents 20. Such results were in accordance with an ionic mechanism in which CF 3 SCl played the role of an electrophilic trifluoromethylthiolating reagent.…”

“…Owing to the electron‐withdrawing effect of the trifluoromethyl group, the sulfur atom was not nucleophilic enough to reform the episulfonium cation. Therefore, the isomerization phenomenon was inhibited 20…”

Fluoroalkylsulfonyl Chlorides Promoted Vicinal Chloro-fluoroalkylthiolation of Alkenes and Alkynes

“…A signal of δ −78.8 ppm (CF 3 SO 3 H) was observed, which is the hydrolysate of CF 3 SO 2 Cl. CF 3 CO 2 H was reported to be an efficient catalyst for the reaction of fluoro­chloro­methane­sulfenyl chloride with alkenes, so we speculated that CF 3 SO 3 H generated from CF 3 SO 2 Cl could also serve as a catalyst for the electrophilic addition. To confirm if CF 3 SO 3 H could promote an electrophilic addition, a reaction using dry DMF under Ar was conducted (Scheme ).…”

Metal‐Free Direct Nucleophilic Perfluoroalkylthiolation with Perfluoroalkanesulfenamides

“…Various solvents were evaluated, but acetone appeared to be the best choice (Table 1, entries 2-7). An increase in the temperature to 80 8Ch ad as omewhat unfavorable effect on the reaction, which may be ar esult of the degradation of the transientC F 3 SI species ( 10,[13][14][15][16][17][18], as is illustrated by the significantly improved yield obtained when KI is chelated by 1,4,7,10,13,16hexaoxacyclooctadecane (18-crown-6, 18-c-6;T able 1, entries 14 and 15). Finally,t he iodide must be used in at least as toichiometrica mount ( Ta ble 1 , entries10, 19, and 20), with the optimal amount being 2.2 equiv (Table 1, entry 21).…”

“…The electrophilica pproach involves the design of shelf-stable reagents to circumvent the toxicity [12] of the historical reagentC F 3 SCl. [13] Thus, various efficient reagents such as trifluoromethanesulfenamides, [14] N-trifluoromethylthiophthalimide, [15] trifluoromethanesulfenates, [16] N-trifluoromethylthiosaccharin, [16a, 17] and at rifluoromethanesulfonyl hypervalent iodoniumy lide [18] have been reportedf or use with this strategy. The nucleophilica pproach involves the use of the CF 3 S À anion, which is relatively unstable [19] and generally requires employing reagents that are able to release the species in situ.…”