Fig. 2. Scope of arenes. Standard reaction conditions: to a solution of 1a (0.3 mmol) in DCE (1.0 mL), Tf₂O (0.33 mmol) was added dropwise at −20 °C. Subsequently, 2 (0.36 mmol) was added. The resulting mixture was slowly warmed to room temperature, and continued to stir under an air atmosphere for 5 h. Isolated yields are given. ^a Ratio was determined by GC-MS analysis of the crude product. ^b 3.0 equivalents of toluene were used. ^c 2.5 equivalents of 1a and Tf₂O were used. ^d The ratio indicates the yields of difuctionalisation and monofuctionalisation. ^e Deacetylated product was obtained.