Table 1.
entry | R | conditionsa | yieldb |
---|---|---|---|
1 | CH2NHTs (2a) | 4 (2.0 equiv), DMF | 17 |
2 | 2a | 4 (2.0 equiv), LiBF4 (2.0 equiv), DMF | 25 |
3 | 2a | 4 (2.0 equiv), LiBr (2.0 equiv), DMF | 45 |
4 | 2a | 4 (2.0 equiv), LiBr (2.0 equiv), DMF/H2O (4:1) | 54 |
5 | 2a | 4 (2.0 equiv), LiBr (2.0 equiv), DMF/H2O (1:4) | 67 |
6 | CH2NHBoc (2b) | 4 (2.0 equiv), LiBr (2.0 equiv), DMF/H2O (1:4) | 99 |
7 | (CH2)4OH (2c) | 4 (2.0 equiv), LiBr (2.0 equiv), DMF/H2O (1:4) | 99 |
8 | 2c | 4 (2.0 equiv), LiBr (2.0 equiv), DMF/H2O (1:4), , no light | 0 |
9 | 2c | no catalyst, 4 (2.0 equiv), LiBr (2.0 equiv), DMF/H2O (1:4) | 0 |
10 | 2c | 4 (1.1 equiv), LiBr (1.1 equiv), DMF/H2O (1:4) | 97 |
11 | 2c | 4 (0.95 equiv), LiBr (0.95 equiv), DMF/H2O (1:4) | 95 |
12 | 2c | 4 (2.0 equiv), no additive, DMF/H2O (1:4) | 72 |
13 | 2c | 4 (2.0 equiv), LiBr (2.0 equiv), DMF | 46 |
Entries 1–6 were degassed (freeze-pump-thaw).
Isolated yield (%) after purification on SiO2.