Synfacts 2007(3): 0259-0259  
DOI: 10.1055/s-2007-968257
Synthesis of Heterocycles
© Georg Thieme Verlag Stuttgart · New York

Ru-Catalyzed [3+2] Cycloaddition of Azides with Alkynes to form Triazoles

Contributor(s): Victor Snieckus, Bärbel Wittel
M. M. Majireck, S. M. Weinreb*
The Pennsylvania State University, University Park, USA
Further Information

Publication History

Publication Date:
20 February 2007 (online)

Significance

The ruthenium-catalyzed [3+2] cycloaddition of internal unsymmetrically disubstituted alkynes with alkyl azides to form 1,4,5-trisubstituted-1,2,3-triazoles in good to excellent yields is reported. Depending on the alkyne substituents, either isomer A or B is regioselectively formed. If R2 is an electron-withdrawing group, A is obtained exclusively; B is obtained as a single regioisomer with propargyl alcohols and amines. On the other hand, if R2 is an alkyl group, a mixture of both isomers is formed.