Visible‐Light‐Induced Metal‐Free Trifluoromethylselenolation of Electron‐Rich Heteroarenes Using the Nucleophilic [Me₄N][SeCF₃] Reagent

Abstract

A metal-free visible-light-promoted regioselective trifluoromethylselenolation of electron-rich heteroarenes has been developed using C-H functionalization. This eco-friendly, atom-economical, and easy-to-operate protocol provides direct [a]

Aromatic Trifluoromethylselenolation via Pd‐catalyzed C−H functionalization

“…A control reaction, without Pd catalyst (Table 2; entry 18), confirmed that the process required a metal catalysis. During our investigations to determine the optimal conditions, the formation of CF 3 SeSeCF 3 dimer was regularly highlighted by 19 F NMR. In order to determine the origin of this dimer, the behavior of 1 a in DMSO at 70°C was monitored by 19 F NMR (Figure 2).…”

“…In view of these results, Pd[CH 3 CN] 2 Cl 2 (20 mol %), without pivalic acid, under air, at 70°C for 24 h (entry 13) was selected as optimal conditions, the best yields being obtained in this case. CuBr [b] OMe 0/9 6 CuBr [c] OMe 8/15 [d] [a] Yields determined by 19 F NMR with PhOCF 3 as internal standard, reported to 2 a or 3 a. Table 2.…”

“…Standard conditions: 1 a (1 equiv., 0.2 mmol), 3 (1 equiv. ), Pd[CH 3 CN] 2 Cl 2 (20 mol%), DMSO (2 mL), 70°C, 24 h. Yields determined by 19 F NMR with PhOCF 3 as internal standard, reported to 3. In parentheses, isolated yields.…”

“…[18] Visible-light-induced trifluoromethylselenolation restricted to nitrogen heteroarenes was also described. [19] These last years, transition metals CÀ H activation to induce aromatic functionalization was explored and welldocumented. [20] Nevertheless, to this day no transition-metal catalyzed trifluoromethylselenolation of aromatic CÀ H bonds were described.…”

Recent Advances in the Development of Direct Trifluoromethylselenolation Reagents and Methods

“…They also conducted this reaction with continuous flow techniques (Scheme 21). [42] Unfortunately, this reaction is limited to electron‐rich heteroarenes. A radical mechanism was supported by EPR experiments.…”