Table 4.
Mechanistic Experiments.

| Entry[a] | Additives | Yield 3e [%][b] |
|---|---|---|
| 1 | none | 0 |
| 2 | Cu(OAc)2 (1 equiv) | 60% |
| 3 | [Cp*Rh(MeCN)3][SbF6]2 (10 mol %) | 10% |
Conditions: 0.05 mmol of 5 in HFIP (0.1 M) at 80 °C for 20 h.
Yields determined by 1H NMR spectroscopic analysis relative to SiMe3Ph as an external standard.