Synthesis 2009(8): 1309-1317  
DOI: 10.1055/s-0028-1088038
PAPER
© Georg Thieme Verlag Stuttgart ˙ New York

Cross-Coupling Reactions of Halopurines with Aryl- and Alkyltrifluoro­borates; The Scope and Limitations in the Synthesis of Modified Purines

Zbyněk Hasník, Radek Pohl, Michal Hocek*
Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Gilead & IOCB Research Center, Flemingovo Nám. 2, 166 10 Prague 6, Czech Republic
Fax: +420(220)183559; e-Mail: hocek@uochb.cas.cz;
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Publikationsverlauf

Received 17 December 2008
Publikationsdatum:
25. März 2009 (online)

Abstract

The scope and limitations of the use of the palladium-catalyzed cross-coupling reactions of diverse alkyl- and aryltrifluoroborates with halopurines have been studied. While aryl- and hetaryltrifluoroborates reacted readily with both 6-chloropurines and 8-bromoadenines to give the corresponding 6- or 8-aryl derivatives in high yields, the alkyltrifluoroborates were much less reactive and, even after thorough optimization, only methyl- and cyclopropyltrifluoroborates gave moderate yields of the desired alkylated purines, while other alkyl-, dialkylaminomethyl- and ethoxycarbonylethyltrifluoroborates did not give any reaction.