Table 1 Optimization of reaction condition for model reaction generating 4a
Number | Catalyst | (Catalyst mol %) | Solvent | Time (h) | Yield (%)a |
|---|---|---|---|---|---|
1 | AgOTf | 1 | CH3CN | 4 | 58 |
2 | AgOTf | 5 | CH3CN | 4 | 78 |
3 | AgOTf | 10 | CH3CN | 4 | 86 |
4 | Sc(OTf)3 | 10 | CH3CN | 4 | 43 |
5 | Ga(OTf)3 | 10 | CH3CN | 4 | 45 |
6 | Zn(OTf)2 | 5 | CH3CN | 4 | 52 |
7 | Ce(OTf)3 | 5 | CH3CN | 4 | 71 |
8 | Cu(OTf)2 | 5 | CH3CN | 4 | 68 |
9 | Ba(OTf)2 | 5 | CH3CN | 4 | 50 |
10 | Yb(OTf)3 | 5 | CH3CN | 4 | 72 |
11 | FeCl3 | 5 | CH3CN | 2 | 59 |
12 | pTSA | 5 | CH3CN | 3 | 71 |
13 | BF3.OEt2 | 5 | CH3CN | 5 | 34 |
14 | Mont. K-10 | -b | CH3CN | 6 | 15 |
15 | SiO2 | -b | CH3CN | 6 | 30 |
16 | AgOTf | 10 | DCM | 10 | 67 |
17 | AgOTf | 10 | DMSO | 10 | 72 |
18 | AgOTf | 10 | DMF | 10 | 62 |
19 | AgOTf | 10 | THF | 10 | 58 |
20 | AgOTf | 10 | [bmim][BF4] | 12 | 31c |
21 | AgOTf | 10 | H2O | 12 | -d |