A convenient synthesis of 1-aryl-1H-1,2,3-triazoles from aliphatic substrates
Qiang Wang1, Xiaonan Shi, Xinying Zhang
1School of Chemistry and Chemical Engineering, Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals, Henan Key Laboratory of Organic Functional Molecule and Drug Innovation, Key Laboratory of Green Chemical Media and Reactions, Ministry of Education, Henan Normal University, Xinxiang, Henan 453007, P. R. China. xinyingzhang@htu.cn xuesen.fan@htu.cn.
Abstract:
A convenient synthesis of 1-aryl-1H-1,2,3-triazoles through the one pot cascade reactions of alkynes with aliphatic azides and allenic ketones is presented. Mechanically, the formation of the title compounds involves a copper-catalyzed cycloaddition of alkyne with 4-azido-3-oxobutanoate to give 3-oxo-4-(1H-1,2,3-triazol-1-yl)butanoate as a key intermediate followed by its [3 + 3] annulation with allenic ketone through Michael addition and intramolecular condensation. A comparison study showed that using aliphatic azide as the substrate is superior to aromatic azide in terms of efficiency and selectivity. Furthermore, the 1-aryl-1H-1,2,3-triazoles bearing a 2'-bromophenyl unit attached on the 2-position of the in situ formed aryl ring obtained herein could be readily transformed into the biologically and pharmaceutically valuable tretracyclic triazolophenanthridines with good yields via a Pd-catalyzed C-H arylation.
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