Table 1.
Conditions Attempted for Conversion of 7a into 8a Using CuI as Catalyst
| Entry | Solvent system | Yield (%)a |
|---|---|---|
| 1 | DMF–t-BuOH (3:1), DIPEA | 28 |
| 2 | DMF–t-BuOH–H2O (3:1:1), DIPEA | 0 |
| 3 | DMF–t-BuOH (1:1), DIPEA | 32 |
| 4 | DMF, DIPEA | 53 |
| 5 | DMF, TMED | 42 |
Yields were calculated after cleaving the resin (solvent MeOH–DCE = 1:1).