Copper‐Catalyzed Trifluoromethylation and Cyclization of Aromatic‐Sulfonyl‐Group‐Tethered Alkenes for the Construction of 1,2‐Benzothiazinane Dioxide Type Compounds

Abstract

A multi‐talented system: An efficient copper‐catalyzed tandem trifluoromethylation/annulation of an electron‐deficient aromatic ring has been developed. This method provides a powerful and straightforward way to synthesize trifluoromethylated 1,2‐benzothiazinane dioxides under mild conditions (see scheme). The mechanism was investigated by a series of kinetic experiments and isotopic labeling studies.

Recent Advances in Radical Difunctionalization of Simple Alkenes

“…Tang, Shi, and coworkers reported copper‐catalyzed trifluoromethylation/annulation of aromatic‐ring‐tethered alkenes with the Togni reagent I by using [Cu(CH 3 CN) 4 ]PF 6 as catalyst with 2,2′‐biquinoline as ligand (Scheme ) . This approach provided not only a practical and convenient methodology for trifluoromethylation, but also straightforward access to highly valuable trifluoromethylated 1,2‐benzothiazinane dioxide derivatives 122 .…”

Progress in the synthesis of δ-sultones

“…Another very interesting radical cyclization approach of sulfonic acid esters and amides 59 was recently reported by Tang, Shi, and co-workers [ 82 ]. By reacting compounds 59 with Togni’s electrophilic CF 3 -transfer reagent 60 under copper-catalysis, the trifluoromethylated δ-sultones/sultames 61 can be obtained in high yields and with a broad substrate scope (Scheme 11 , upper reaction).…”

“…It should be noted that the authors mainly used amides 59 (giving the sultames) but also proved the feasibility of this concept for a small variety of sulfonates to access the corresponding sultones 61 . Carefully chosen control experiments clearly support a radical mechanism for this transformation [ 82 ]. Very recently, Alcaide, Almendros, and co-workers developed a metal free radical cyclization strategy to access highly functionalized δ-sultones 64 starting from the radical precursor 62 and TEMPO ( 63 ) in the presence of trifluoroacetic acid [ 83 ].…”

Perfluoroalkylation of Unactivated Alkenes with Acid Anhydrides as the Perfluoroalkyl Source

“…[3][4][5][6][7] We have developed various difunctionalization-type trifluoromethylation reactions using the Togni reagent, [4e,5a, 6a, 7] and ad iverse array of trifluoromethylated compounds can now be accessed. [3][4][5][6][7] We have developed various difunctionalization-type trifluoromethylation reactions using the Togni reagent, [4e,5a, 6a, 7] and ad iverse array of trifluoromethylated compounds can now be accessed.…”

“…Recently,a lkene trifluoromethylation has been realized through the development of excellent electrophilic trifluoromethylating reagents such as the Togni reagent and the Umemoto reagent, which enable the direct construction of synthetically important organic frameworks bearing atrifluoromethyl group on an sp 3 carbon. [3][4][5][6][7] We have developed various difunctionalization-type trifluoromethylation reactions using the Togni reagent, [4e,5a, 6a, 7] and ad iverse array of trifluoromethylated compounds can now be accessed. The high cost and multistep preparation of these sophisticated reagents,however,might hinder industrial application.…”