Synfacts 2005(0): 0027-0027  
DOI: 10.1055/s-2005-865374
Synthesis of Heterocycles
© Georg Thieme Verlag Stuttgart · New York

Superacid-Promoted Reactions of Pyrazole­-carboxaldehydes and the Role of Dicationic Electrophiles

Contributor(s): Victor Snieckus, Zhongdong Zhao
D. A. Klumpp*, P. J. Kindelin, A. Li
Northern Illinois University, DeKalb, USA
Weitere Informationen

Publikationsverlauf

Publikationsdatum:
20. Juli 2005 (online)

Significance

Treatment of pyrazolecarboxaldehydes with super acids leads to the formation of dicationic species which are highly reactive for electrophilic diarylation even with weakly nucleophilic arenes. Thus a variety of substituted pyrazolecarboxaldehydes condense with benzene to provide side-chain substituted products. The mechanism involving a dicationic intermediate is supported by low temperature 13C NMR studies.