1,2,3-Triazolium units are present in various functionalized molecules, including mesoionic carbenes, organocatalysts, and anion recognition receptors. While the oxidative [3 + 2] cycloaddition of triazenes with alkynes is one of the most efficient methods to construct the 1,2,3triazolium skeleton, the effect of reaction parameters and substrate scope in the reaction has not been fully studied. Herein, we developed a practical protocol for the synthesis of 1,2,3-triazolium salts and significantly expanded the substrate scope of triazenes and alkynes. Also, an efficient method for the deprotonative functionalization of 1,2,3-triazolium salts was achieved.

Although halogen-bonding has been utilized as an emerging means for activation of substrates, the use of the interaction for activation of relatively low Lewis basic electrophiles such as carbonyl compounds is still limited. Herein, we developed the halogen-bonding-donor donor catalyzed cyanosilylation of aldehydes via a synergistic activation mechanism, which were supported by a combined computational and experimental approach. The substrate scope for the reaction and the chemoselectivity of cationic XB-donors are described.