Boron Lewis Acid-Catalyzed Hydroboration of Alkenes with Pinacolborane: BArF3Does What B(C6F5)3Cannot Do!
| Autor: | Martin Oestreich, Sebastian Kemper, Hendrik F. T. Klare, Qin Yin |
|---|---|
| Rok vydání: | 2016 |
| Předmět: |
Trifluoromethyl
010405 organic chemistry Organic Chemistry Regioselectivity Boranes General Chemistry Borane 010402 general chemistry Metathesis 01 natural sciences Medicinal chemistry Catalysis 0104 chemical sciences Adduct chemistry.chemical_compound Hydroboration chemistry Organic chemistry Lewis acids and bases |
| Zdroj: | Chemistry - A European Journal. 22:13840-13844 |
| ISSN: | 0947-6539 |
| Popis: | The transition-metal-free hydroboration of various alkenes with pinacolborane (HBpin) initiated by tris[3,5-bis(trifluoromethyl)phenyl]borane (BArF3 ) is reported. The choice of the boron Lewis acid is crucial as the more prominent boron Lewis acid tris(pentafluorophenyl)borane (B(C6 F5 )3 ) is reluctant to react. Unlike B(C6 F5 )3 , BArF3 is found to engage in substituent redistribution with HBpin, resulting in the formation of ArF Bpin and the electron-deficient diboranes [H2 BArF ]2 and [(ArF )(H)B(μ-H)2 BArF2 ]. These in situ-generated hydroboranes undergo regioselective hydroboration of styrene derivatives as well as aliphatic alkenes with cis diastereoselectivity. Another ligand metathesis of these adducts with HBpin subsequently affords the corresponding HBpin-derived anti-Markovnikov adducts. The reactive hydroboranes are regenerated in this step, thereby closing the catalytic cycle. |
| Databáze: | OpenAIRE |
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