Table 1.
Condition optimization
| Entry |  |
Deviation from above | Yield [%] |
|---|---|---|---|
| 1 | B | None | 79 (72)b |
| 2 | B | Co(hfacac)2 instead of Co(acac)2 | 25 |
| 3 | B | L5 instead of (R, R)-tBu-Pybox | 75 (70)b |
| 4 | B | L6 instead of (R, R)-tBu-Pybox | 45 |
| 5 | B | DCE instead of PhCF3 | 32 |
| 6 | B | PhCl instead of PhCF3 | 72 |
| 7 | B | 100 oC instead of 120 oC | 8 |
| 8 | B | 10 bar CO instead of 40 bar CO | 42 |
| 9c | B | ethylene instead of 2 h | 83 (79)b |
| 10d | B | ethylene instead of 2 h | 81 (78)b |
| 11e | B | ethylene instead of 2 h | 72 |
Reaction conditions: a1a (10 equiv.), 2a (0.6 mmol), 3a (0.3 mmol), Co(acac)2 (5 mol%), (R, R)-tBu-Pybox (5 mol%), DTBP (3 equiv.), CO (40 bar), PhCF3 (0.2 M), 120 oC, 20 h, yields were determined by GC-FID analysis. b Isolated yield. c10 bar ethylene, 40 bar CO. d 10 bar ethylene and 20 bar CO. e5 bar ethylene and 5 bar CO. acac acetylacetone, hfacac hexafluoroacetylacetone, DTBP di-tert-butyl peroxide.