“…The reaction with PIDA produced a moderate yield of 20b, compared to the reaction with PIFA (Table 2, Entries 2, 3, 5). As previously predicted, [33][34][35][36][37] considerable amounts of by-products 21a-d were obtained in cases using acetic acid, acetonitrile, dimethoxyethane, and isopropanol as solvents due to the gen- eration of a cation (22) or a radical followed by nucleophilic attack of the solvents (Table 2, Entries 4-8). Fortunately, the best yield (85%) was obtained in the reaction conducted with PIFA in trifluoroethanol at room temperature ( Table 2, Entry 1).…”