Table 3.
Substrate Scope of Two-Step Trifluoromethylation of Phenol
 
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Standard condition of xanthate formation: 1 (2.0 mmol), 6 (2.0 mmol), Et3N (2.0 mmol), MeCN (10 mL), 0 °C, 1 h.
Condition A: 2 (0.5 mmol), XtalFluor-E (2.5 mmol), TCCA (0.5 mmol), H2O (0.5 mmol), and (CH2Cl)2 (10 mL), 80 °C.
Condition B: 2 (0.5 mmol), XtalFluor-E (1.5 mmol), NFSI (1.5 mmol), and (CH2Cl)2 (10 mL), 80 °C.
NMR yields determined by 19F NMR using PhCF3 as an internal standard were reported in the parentheses.
Reagent 7 was used instead of 6.
Reagent 5 (1.5 equiv), Cs2CO3 (2.0 equiv), and DMF (0.1 M) were used instead of the standard conditions.
Selectfluor (0.5 mmol, 1.0 equiv) was added.
Selectfluor (1.0 mmol, 2.0 equiv) was added.