Table 1 Optimization of the Fe-catalyzed radical Markovnikov hydrobromination and hydroiodination with various X-transfer reagents using alkenes 1a and 1b as model substrates
From: Iron-catalyzed radical Markovnikov hydrohalogenation and hydroazidation of alkenes
| |||||
|---|---|---|---|---|---|
Entrya | Fe–H source | Solvent | Radical trap | Conversion | Yield |
1 | Fe(dpm)3, 4 (2.0 eq.) | THF/iPrOH | 2a (1.5 eq.) | 98% (1a) | 85% (3a) |
2 | Fe(dpm)3, PhSiH3 (2.0 eq.) | THF/iPrOH | 2a (1.5 eq.) | 99% (1a) | 79% (3a) |
3 | Fe(acac)3, 4 (2.0 eq.) | THF/iPrOH | 2a (1.5 eq.) | 90% (1a) | 79% (3a) |
4 | Fe(acac)3, PhSiH3 (2.0 eq.) | THF/iPrOH | 2a (1.5 eq.) | 93% (1a) | 56% (3a) |
5 | Fe(acac)3, PhSiH3 (2.0 eq.) | MeOH | 2a (1.5 eq.) | 98% (1a) | 76% (3a) |
6b | Fe(acac)3, PhSiH3 (1.0 eq.) | MeOH | 2a (1.5 eq.) | 94% (1a) | 84% (3a) |
7c | Fe(acac)3, PhSiH3 (1.0 eq.) | MeOH | 2a (1.5 eq.) | 96% (1a) | 81% (3a) |
8b | Fe(acac)3, PhSiH3 (1.0 eq.) | MeOH | 2a (1.2 eq.) | 98% (1a) | 98% (3a) |
9 | Fe(acac)3, PhSiH3 (1.5 eq.) | MeOH | 2a (1.5 eq.) | 41% (1b) | 9% (3b) |
10 | Fe(dpm)3, 4 (2.0 eq.) | THF/iPrOH | 2a (2.0 eq.) | 57% (1b) | 27% (3b) |
11b | Fe(dpm)3, 4 (2.0 eq.) | THF/iPrOH | 2a (1.1 eq.) | 89% (1b) | 79% (3b) |
12b | Fe(dpm)3, 4 (1.2 eq.) | THF/iPrOH | 2a (1.1 eq.) | 90% (1b) | 81% (3b) |
13 | Fe(acac)3, PhSiH3 (2.0 eq.) | MeOH | 2b (3.0 eq.) | 33% (1a) | 12% (5a) |
14 | Fe(acac)3, PhSiH3 (2.0 eq.) | MeOH | 2c (3.0 eq.) | n.d. (1a) | 8% (5a) |
15 | Fe(dpm)3, 4 (2.0 eq.) | THF/iPrOH | 2d (3.0 eq.) | 49% (1a) | 0% (5a) |
16 | Fe(acac)3, PhSiH3 (2.0 eq.) | MeOH | 2e (3.0 eq.) | 33% (1a) | 25% (5a) |
17 | Fe(acac)3, PhSiH3 (2.0 eq.) | MeOH | 2f (3.0 eq.) | 0% (1a) | 0% (5a) |
18d | Fe(acac)3, PhSiH3 (1.0 eq.) | MeOH | 2e (1.0 eq.) | 87% (1a) | 84% (5a) |
19e | Fe(acac)3, PhSiH3 (1.0 eq.) | MeOH | 2e (1.0 eq.) | 81% (1a) | 81% (5a) |
