Halogen-Substituted Mesoionic-Carbene/Palladium Complexes for Catalytic Arylation of Aldehydes

Various halogenated mesoionic-carbene-coordinated palladium complexes (denoted as TAPs and e-TAPs) were prepared using triazolylidene precursors that were synthesized in only two steps via a click reaction. Among the prepared complexes, Br-e-TAP showed optimal catalytic activity for the arylation of aldehydes with arylboronic compounds. Additionally, the Br-e-TAP catalyst assisted in synthesizing a wide range of functionalized diarylmethanols and arylmethanols in 29%95% yields with loadings of 0.2–0.6 mol% Pd.