ZnI₂-Catalyzed Aminotrifluoromethylation Cyclization of Alkenes Using PhICF₃Cl

Abstract

We report here an alternatively catalytic aminotrifluoromethylation of alkenes using PhICF 3 Cl as a bifunctional reagent along with ZnI 2 as a dual catalyst. A combined catalytic strategy was established for the intramolecular aminotrifluoromethylation of 4-pentenamines. As a result, a set of 2-trifluoroethyl-pyrrolidines was obtained in a high selectivity. Mechanism studies revealed that the reaction included an iodine anion-catalyzed radical chlorotrifluoromethylation of alkenes and a sequential Lewis acid-promoted aminocyclization of the resulting chlorotrifluoromethylated intermediates.

Combined Approach of Hypervalent Iodine Reagents and Transition Metals in Organic Reactions

“…Further, cyclized product is obtained by intramolecular amination and intermolecular chlorination. On other hand, cation is regenerated by ZnCl 2 from trifluoromethylated species [59] …”

Recent Advances on the Halo- and Cyano-Trifluoromethylation of Alkenes and Alkynes

“…It should be mentioned that there were also some related reports on the halo-perfluoroalkylation of unsaturated bonds which just contained one example about trifluoromethylation [ 84 , 85 , 86 , 87 , 88 , 89 , 90 , 91 , 92 , 93 , 94 , 95 ].…”

Alkoxysulfenylation of alkenes: development and recent advances

“…Cyclofunctionalization reactions represent an important strategy for the synthesis of functionalized (hetero)cyclic structures from simple starting materials that would otherwise be difficult to prepare. 29 In this family of reactions, sulfetherification of alkenols offers a promising strategy for the selective synthesis of sulfenyl-substituted oxacycles within a single click. One of the earliest reports on the cyclizative sulfenylation of alkenols was published by Capozzi and co-workers in 1981, 30 who showed that the treatment of o -allylphenols 33 with methyl(bismethy1thio)sulfonium hexachloroantimonate 34 in the absence of any catalyst or additive in anhydrous DCM, resulted in the formation of methylthio-substituted dihydrobenzofurans 35 in good yields and selectivities ( Scheme 12a ).…”