Metal-free Regioselective Azide-alkyne [3+2]-Cycloaddition in Water

Kloß, Florian; Köhn, Uwe; Hager, Martin D.; Jahn, Burkhard O.; Görls, Helmar; Schubert, Ulrich S.
Abstract:
[3+2]-cycloaddition reactions of aromatic azides and silylated alkynes in aqueous media yield 1,5-disubstituted-4-(trimethyl-silyl)-1H-1,2,3-triazoles. The formation of the 1,5-isomer is highly favored in this metal-free cycloaddition, which could be proven by 1D selective NOESY and X-ray investigations. Additionally, DFT calculations corroborate the outstanding favoritism regarding the 1,5-isomer. The described method provides a simple alternative protocol to metal-catalyzed “click chemistry” procedures, widening the scope for regioselective heavy-metal-free synthetic applications.
Year:
2011
Type of Publication:
Article
Journal:
Chemistry – An Asian Journal
Volume:
10
Pages:
2816 - 2824