Table 1.
Selected Optimization of the Ni‐catalyzed Catellani annulation
| ||
|---|---|---|
| Entrya | Variations from the standard condition | Yield of 3a/4/5/6 (%)b |
| 1 | None | 99/0/0/1 |
| 2 | w/o Ni(cod)2 | 0/0/0/0 |
| 3 | w/o PPh2Me | 2/0/7/3 |
| 4 | w/o BTMG | 0/0/0/0 |
| 5 | other ligands instead of PPh2Me | listed below |
| 6 | other base instead of BTMG | listed below |
| 7 | other solvent instead of benzene | listed below |
| 8 | 1-chloronaphthalene instead of 1a | 1/18/2/4 |
| 9 | 1-bromonaphthalene instead of 1a | 3/31/6/6 |
| 10 | 1-iodonaphthalene instead of 1a | 9/39/11/13 |
| 11c | 5 mol% Ni(cod)2/7.5 mol% PPh2Me was used | 82/0/9/4 |
| ||
Reaction conditions: 1a (0.1 mmol, 1.0 equiv), 2 (0.4 mmol, 4.0 equiv), Ni(cod)2 (0.01 mmol, 10 mol%), PPh2Me (0.015 mmol, 15 mol%), BTMG (0.3 mmol, 3.0 equiv), benzene (0.25 mL), 50 °C, 48 h.
Yields were determined by 1H NMR using CH3NO2 as an internal standard.
Reaction temperature was 70 °C.