Affiliation:
1. Department of Chemistry University of Toronto 80 St. George Street Toronto Ontario M5S 3H6 Canada
2. Institute of Drug Discovery Technology Ningbo University Ningbo 315211 Zhejiang China
3. Mulliken Center for Theoretical Chemistry Clausius Institut für Physikalische und Theoretische Chemie Rheinische Friedrich-Wilhelms-Universität Bonn Beringstrasse 4 53115 Bonn Germany
Abstract
AbstractB(C6F5)3 and the corresponding anion [B(C6F5)4]− are ubiquitous in main group and transition metal chemistry. Known derivatives are generally limited to the incorporation of electron donating substituents. Herein we describe electrophilic fluorination and dearomatization of such species using XeF2 in the presence of BF3 or Lewis acidic cations. In this fashion the anions [HB(C6F5)3]−, [B(C6F5)4]− and [(C6F5)3BC≡NB(C6F5)3]−, are converted to [FB(C6F7)3]−, [B(C6F7)4]−, and [(C6F7)3BC≡NB(C6F7)3]−, respectively. Similarly, the borane adducts (L)B(C6F7)3 (L=MeCN, OPEt3) are produced. These rare examples of electrophilic attack of electron deficient rings proceed as [XeF][BF4] acts as a frustrated Lewis pair effecting fluorination and dearomatization of C6F5 rings.