Table 1.
Entry | Activator | 2 aYield [%] | 3 aYield [%] |
---|---|---|---|
1 | – | 0 | 0 |
2 | TMSOTf | 93 | 0 |
3 | TBDMSOTf | 88 | 0 |
4 | BF3⋅OEt2 | 18 | 67 |
5[b] | camphorsulfonic acid | 0 | 92 |
6[c] | TsOH⋅H2O | 8 | 64 |
Reagents and conditions: a) PhI(OCOCF3)2 (1 equiv), activator (2 equiv), MeCN, RT, 30 min;
When the reaction was performed by using substrate (E)-1 f, rearranged product 3 f was obtained in 89 % yield.
Koser’s reagent Ph(OH)OTs was used for this reaction. In addition to 2 a and 3 a, compound 4 a was observed in 8 % yield.