Table 1 Optimization of reaction conditions
From: Expedient syntheses of N-heterocycles via intermolecular amphoteric diamination of allenes
| |||
|---|---|---|---|
Entry | X | Reaction conditions (equiv.) | Yield of 13a (yield of 14b) |
1 | Cl | CuI (0.1), Cs2CO3 (1.5), THF, RT, 24 h | 20% |
2 | Cl | Cs2CO3 (1.5), THF, RT, 24 h | 0% |
3 | Cl | KI (0.2), Cs2CO3 (1.5), THF, RT, 24 h | 35% |
4 | Cl | KI (0.5), Cs2CO3 (1.5), THF, RT, 24 h | 75% |
5 | Cl | KI (1.0), Cs2CO3 (1.5), THF, RT, 24 h | 79% (65%) |
6 | Cl | KI (2.0), Cs2CO3 (1.5), THF, RT, 24 h | 79% |
7 | Cl | KI (1.0), Cs2CO3 (1.5), MeCN, RT, 24 h | 63% |
8 | Cl | NaI (1.0), Cs2CO3 (1.5), THF, RT, 24 h | 54% |
9 | Cl | TBAI (1.0), Cs2CO3 (1.5), THF, RT, 24 h | trace |
10 | Cl | KI (1.0), Cs2CO3 (1.5), THF, 40 °C, 24 h | 78% |
11 | H | NCS (1.05), THF, 1 h, then 12, KI (1.0), Cs2CO3 (1.5), RT, 24 h | 79% |
12 | H | NIS (1.05), THF, 1 h, then 12, Cs2CO3 (1.5), RT, 24 h | 86% (70%) |
13 | H | as entry 12, but gram scale | --% (76%) |
