Table 1.
entry | acid/base | equivalent | solvent | yields (%)c |
---|---|---|---|---|
1 | PTSA | 1 | THF | 61 |
2 | PTSA | 1 | DMF | 75 |
3 | KOtBu | 0.5 | DMF | 55 |
4 | KOtBu | 1 | DMF | 65 |
5a | PTSA | 1 | DMF | 8 |
6b | PTSA | 1 | DMF | 0 |
Reaction Carried out at 70° C.
Reaction carried out at room temperature.
Isolated yields (flash chromatography). PTSA: para toluene sulfonic acid