Table 1. Selected Screening Results for Direct C–H Alkylation of 1 Using Alkyl Bromides.
| entry | catalysta | base | additive | solvent | tempb | time | conversion of 1 | conversion to 2 |
|---|---|---|---|---|---|---|---|---|
| 1 | [RuCl2(p-cymene)]2 (0.1 equiv) | K2CO3 (3 equiv) | PPh3 (0.05 equiv) cyclohexanol (1 equiv) | o-xylene | 140 °C | 24 h | 56% | 23% |
| 2 | [RuCl2(p-cymene)]2 (0.1 equiv) | K2CO3 (3 equiv) | KOPiv (0.3 equiv) cyclohexanol (1 equiv) | o-xylene | 140 °C | 24 h | 60% | 20% |
| 3 | [RhCl(cod)]2 (0.1 equiv) | K2CO3 (3 equiv) | cyclohexanol (1 equiv) | o-xylene | 140 °C | 24 h | 70% | 31% |
| 4 | [RhCl(cod)]2 (0.1 equiv) | K2CO3 (3 equiv) | cyclohexanol (1 equiv) | toluene | 140 °C | 24 h | 73% | 37% |
| 5 | [RhCl(cod)]2 (0.1 equiv) | K2CO3 (3 equiv) | cyclohexanol (1 equiv) | toluene | 160 °C | 24 h | 97% | 70% (56%)d |
| 6 | [RhCl(cod)]2 (0.1 equiv) | K2CO3 (3 equiv) | toluene | 160 °C | 24 h | 98% | 70% |
a
Equivalents based on monomer unit.
b
Reaction block temperatures and not inside temperatures of the reaction mixtures.
c
Based on GC analysis of the reaction mixture with dodecane as internal standard.
d
Isolated yield.