Entry | Reaction condition | Yield (%) | Time | Ref. |
1 | Reflux ethanol or acetic acid | 71 | 5 - 6 h | [30] |
2 | I2 (10 mol%), H2O, 100˚C, 1.01 × 105 Pa | 71 | 28 min | [15] |
3 | DBU, r.t. | - | - | [32] |
4 | SDS (20 mol%), water, 60˚C | 98 | 3 | [22] |
5 | TBAB, water | 91 | 25 min | [23] |
6 | TBAB, solvent-free | 91 | 21 min | [23] |
7 | TiO2/ | 88 | 30 | [30] |
8 | SiO2Cl, CH2Cl2, 40˚C | 85 | 3.5 | [28] |
9 | DBSA (25 mol%), H2O:Ethanol, 80˚C | 90 | 60 min | this work |
10 | DBSA (25 mol%), H2O:Ethanol, MV | 90 | 4.5 min | this work |