Brønsted acid catalyzed N2‑selective alkylation of 1,2,3-triazoles with trichloroacetimidates

Abstract

A Brønsted acid catalyzed alkylation method for 1,2,3-triazoles is described using trichloroacetimidates as the electrophiles. These conditions were selective, with a strong preference of N2 alkylation product, often in high yield. The ratio of N2:N1 alkylation is sensitive to both the type of solvent used and the reaction concentration. The optimal results were obtained with a non-polar solvent at higher dilutions. Both 1,2,3-triazoles and 1,2,3-benzotriazoles could be alkylated under these conditions, providing access to N2 substituted 1,2,3-triazoles in good yields.