Table 1.
| ||||
---|---|---|---|---|
no. | catalyst (2.5 mol %) | Lewis acid (5.0 mol %) | solvent 0.06 M | yieldb (%) |
1 | Rh2(OAc)4 | AgOCOCF3 | toluene | NR |
2 | Rh2(pfb)4 | AgOCOCF3 | toluene | NR |
3 | Rh2(dosp)4 | Al(OTf)3 | toluene | 63 |
4 | Rh2(oct)4 | AgOCOCF3 | toluene | 53 |
5 | Rh2(oct)4 | AgOCOCF3 | hexane | 67 |
6 | Rh2(oct)4 | - | hexane | NRc |
7 | Rh2(oct)4 | AgOTf | hexane | NR |
8 | Rh2(oct)4 | CsF | hexane | NR |
9 | Rh2(oct)4 | Zn(OTf)2 | hexane | NR |
10 | Rh2(oct)4 | Y(OTf)3 | hexane | NR |
11 | Rh2(oct)4 | AgOCOCF3 | DCM | NR |
12 | Rh2(oct)4 | AgOCOCF3 | DCE | NR |
13 | Rh2(oct)4 | AgOCOCF3 | THF | NR |
14 | Rh2(oct)4 | CF3SO3H | hexane | Dec.d |
15 | Rh2(oct)4 | CF3CO2H | hexane | Dec. |
All reactions were performed at 70 °C for 12 h with 0.2 mmol of 1a and 0.3 mmol of alkyne;
Isolated yield;
NR = No Reaction;
Dec. = Decomposition.