A comparison of the reaction yield and turnover number (TON) calculated with respect to the formation of PhCH(OH)CH2CH2Ph in the β-alkylation reaction of the representative 1-phenylethanol and benzyl alcohol substrates as catalyzed by well-defined transition metal–NHC complexes known in the literature.
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|---|---|---|---|---|---|---|---|---|---|
| S. No. | Catalyst | Base | Time (h) | Solvent | Catalyst loading | Temperature | Yield (%) | TON | Reference |
| 1 |
|
KOH (2.5 mmol) | 40 | Toluene (0.3 mL) | 1 mol% | 110 °C | 100 (by 1H NMR) | 95a | 44 |
| 2 |
|
KOH (1 mmol) | 8 | Toluene (0.3 mL) | 1 mol% | 110 °C | 92 (by 1H NMR) | 92 | 45 |
| 3 |
|
KOH (1.0 mmol) | 8 | Toluene (0.3 mL) | 1 mol% | 110 °C | 88 (by 1H NMR) | 88 | 45 |
| 4 |
|
NaOiPr (0.8 mmol) | 12 | Solvent free | 0.001 mol% | 125 °C | 97 (isolated) | 97 000 | 24 |
| 5 |
|
NaOiPr (1.00 mmol) | 3 | Toluene (2.0 mL) | 1 mol% | 110 °C | 72 (isolated) | 72 | 32 |
| 6 |
|
NaOiPr (1.00 mmol) | 3 | Toluene (2.0 mL) | 1 mol% | 110 °C | 68 (isolated) | 68 | 32 |
| 7 |
|
NaOiPr (1.00 mmol) | 3 | Toluene (2.0 mL) | 1 mol% | 110 °C | 70 (isolated) | 70 | Present work |
| 8 |
|
NaOiPr (1.00 mmol) | 3 | Toluene (2.0 mL) | 1 mol% | 110 °C | 72 (isolated) | 72 | Present work |
| 9 |
|
NaOiPr (1.00 mmol) | 3 | Toluene (2.0 mL) | 1 mol% | 110 °C | 68 (isolated) | 68 | Present work |
a
With respect to each metal of the tetra nuclear complex.