Access to Functionalized Azolium Salts via Regiospecific Alkylation with Unactivated Alkenes: Scope and Mechanistic Insight

Abstract In this study, we present a Ru II ‐catalyzed one‐step approach for the synthesis of diverse ortho ‐alkylated N‐aryl‐(benz)imidazolium salts (>50 examples) directly from the readily available azolium salts and unactivated alkenes. This method offers broad substrate scope with a range of azolium salts and a wide spectrum of alkenes, including several biologically relevant motifs. Moreover, this protocol is equally effective for di‐ ortho ‐alkylation. Finally, various control experiments that include the isolation of key catalytic intermediates, deuterium labelling studies established the reaction pathway and DFT calculations provided insight toward the selective formation of linear over the branched ortho ‐alkylated product.