Table 12. Screening the Hydroxyl-yne Reaction between Benzyl Alcohol and Methyl Propiolate Using Various Solvents and Different Trivalent Phosphine Catalysts82.
| catalyst | solvent | time (min) | conversion (%) | E/Z |
|---|---|---|---|---|
| PPh3 | C6H6 | 480 | 86 | 75/25 |
| PPh3 | CH2Cl2 | 480 | 85 | 83/17 |
| PPh3 | THFa | 480 | 62 | 75/25 |
| PPh3 | MeCNb | 480 | >98 | 83/17 |
| PBu3 | C6H6 | 10 | 83 | 100/0 |
| PBu3 | CH2Cl2 | 10 | >98 | 100/0 |
| PBu3 | THF | 10 | >98 | 100/0 |
| PBu3 | MeCN | 10 | >98 | 99/1 |
| P(c-Hex)3 | MeCN | 120 | 66 | 88/12 |
| P(OMe)3 | MeCN | 480 |
a
THF = tetrahydrofuran.
b
MeCN = acetonitrile.