Protonation of the Heterocyclic Cp-Anion Equivalent [Pyrrolyl-B(C6F5)3]Li − Formation of a Useful Neutral Brønsted Acid for the Generation of Homogeneous Metallocene Ziegler Catalysts
✍ Scribed by Gerald Kehr; Rolf Roesmann; Roland Fröhlich; Christiane Holst; Gerhard Erker
- Publisher
- John Wiley and Sons
- Year
- 2001
- Tongue
- English
- Weight
- 290 KB
- Volume
- 2001
- Category
- Article
- ISSN
- 1434-1948
No coin nor oath required. For personal study only.
✦ Synopsis
N-pyrrolyllithium (1) adds to B(C 6 F 5 ) 3 to yield [(C 4 H 4 N)B(C 6 F 5 ) 3 ]Li (3). The corresponding monoetherate (3•OEt 2 ) was characterized by X-ray diffraction and shows an η 5 coordination of the pyrrolyl moiety to the lithium cation. Treatment of 3 with HCl in ether leads to H + addition at a pyrrolyl α-position to yield the neutral dipolar Brønsted acid system [(C 4 H 5 N)B(C 6 F 5 ) 3 ] (4). The reagent 4 can be used to protonate Cp 2 Zr(CH 3 ) 3 to yield [Cp 2 Zr(CH 3 ) + (C 4 H 4 N)B-(C 6 F 5 ) 3 -] (6) and methane. H + transfer from 4 to (butadiene)-