Substituted functional olefins through lateral sequential lithiation/silylation/condensation of tertiary aromatic amides: A ligand for phosphane-free palladium-catalyzed Suzuki coupling reactions

摘要

An unprecedented lateral sequential lithiation/silylation/condensation of tertiary aromatic amides has been developed that provides an efficient method to build up functional olefins in good yields. In addition, we have established an efficient and simple method that involves UV/Vis, fluorescence, and NMR analyses, to detect the interaction between transition-metal salts and functional olefins containing tertiary amides. This has enabled a highly efficient palladium-catalyzed Suzuki coupling reaction in the presence of tertiary aromatic amide-derived olefin ligands to be developed. The best results were obtained by employing 2 mol-% Pd(OAc) _2, 2 equiv. Cs _2CO _3, a reaction temperature of 80 °C, dioxane as the solvent, and phosphane-free olefin 2d as ligand.