Table 1.
Starting material consumption and product formation from various catalysts.
| Entry | Catalyst | Temperature, 0 °C |
Temperature, 40 °C |
||||
|---|---|---|---|---|---|---|---|
| Yield (%)a | Conversiona (%) | Ratio of yield/conversion (%)b | Yield (%) | Conversion (%) | Ratio of yield/conversion (%) | ||
| 1 | H2SO4 (98%) | 9.4 ± 1.2 | 79.5 ± 0.6 | 11.8 | 61.4 ± 0.3 | 98.8 ± 0.1 | 62.1 |
| 2 | H3PO4 (85%) | 2.2 ± 2.4 | 53.6 ± 4.0 | 4.1 | 40.9 ± 0.2 | 72.1 ± 0.1 | 56.7 |
| 3 | HNO3 (70%) | 0 | 44.8 ± 2.1 | 0 | 38.7 ± 1.2 | 71.5 ± 0.5 | 54.1 |
| 4 | HClO4 (70%) | 63.3 ± 0.8 | 98.3 ± 0.2 | 64.3 | 80.1 ± 3.0 | 99.6 ± 0.6 | 80.4 |
| 5 | HCl (38%) | 2.6 ± 2.4 | 55.4 ± 4.1 | 4.8 | 47.1 ± 3.9 | 84.8 ± 3.1 | 55.6 |
| 6 | CH3SO3H | 4.4 ± 0.8 | 69.9 ± 3.3 | 6.3 | 61.4 ± 0.3 | 97.9 ± 0.1 | 62.6 |
| 7 | p-TsOH•H2O | 11.8 ± 0.3 | 78.8 ± 1.1 | 14.9 | 61.5 ± 0.1 | 100 | 61.5 |
| 8 | CF3COOH | 0 | 22.8 ± 6.0 | 0 | 5.1 ± 2.4 | 24.7 ± 5.4 | 20.7 |
| 9 | Cl3CCOOH | 0 | 17.3 ± 0.5 | 0 | 1.3 ± 0.3 | 8.2 ± 2.9 | 16.3 |
| 10 | SnCl4 | 48.6 ± 1.5 | 96.9 ± 0.2 | 50.1 | 78.5 ± 0.3 | 100 | 78.5 |
| 11 | SbCl5 | 51.1 ± 0.3 | 98.8 ± 0.2 | 51.6 | 58.8 ± 0.6 | 100 | 58.8 |
| 12 | BF3•OEt2 | 52.3 ± 0.4 | 99.0 ± 0.1 | 52.8 | 70.0 ± 0.2 | 100 | 70.0 |
| 13 | BF3•THF | 56.7 ± 0.2 | 99.0 ± 0.1 | 57.2 | 65.9 ± 0.3 | 100 | 65.9 |
| 14 | Eu(OTf)3 | 32.8 ± 6.4 | 91.1 ± 4.5 | 36.1 | 88.2 ± 5.4 | 97.2 ± 0.9 | 88.2 |
| 15 | Tb(OTf)3 | 25.8 ± 2.8 | 83.9 ± 1.3 | 30.8 | 85.5 ± 3.1 | 91.8 ± 1.2 | 93.2 |
| 16 | Er(OTf)3 | 23.6 ± 1.4 | 82.3 ± 0.8 | 28.7 | 93.2 ± 0.3 | 95.7 ± 0.1 | 97.4 |
| 17 | Ho(OTf)3 | 21.0 ± 0.9 | 80.6 ± 0.2 | 26.1 | |||
| 18 | Yb(OTf)3 | 20.0 ± 1.0 | 78.1 ± 0.7 | 25.6 | |||
a
Yields of product and conversions of substrate are determined by UHPLC. Yield ± conversion = mean ± SE (standard error) (n=3)
b
Percentage ratio of yield to conversion.