Table 2. Exploring various alkylboron compounds a .
| |||
Alkylboron | Reduction potential | Result | Drawbacks |
>2.5 V vs. SCE | No conversion | • Air sensitive | |
• Poor redox properties | |||
>2.5 V vs. SCE | No conversion | • Limited commercial availability | |
• Poor atom economy | |||
• Poor redox properties | |||
>2.5 V vs. SCE | <5% conversion | • Air sensitive | |
• Poor atom economy | |||
• Poor redox properties | |||
+1.1 V vs. SCE | No conversion | • Limited commercial availability | |
• Hydrolytically unstable | |||
• Poor atom economy | |||
aReactions were run with heteroarene (1.0 equiv.), alkylboron reagent (1.0 equiv.), MesAcr (5 mol%), K2S2O8 (2.0 equiv.), trifluoroacetic acid (1.0 equiv.) in MeCN/H2O (1 : 1) on 0.2 mmol scale.