(E)-N-(pyren-1-ylmethylene)benzenamine: efficient promoter for additive-free palladium catalyzed aerobic oxidative coupling of arylboronic acids and terminal alkynes

A highly productive protocol for the synthesis of internal alkynes by the carbon–carbon cross-coupling reactions of electronically different arylboronic acids with substituted phenylacetylenes was described by employing (E)-N-(pyren-1-ylmethylene)benzenamine with Pd(OAc) 2 . The influence of reaction parameters such as solvent, base and reaction temperature in this carbon–carbon cross-coupling reaction was also investigated. The substrate scope could be expanded to electron-poor alkynes, for which the conventional Sonogashira reaction gives poor yields. Moderate to excellent yield was obtained in the oxidative Sonogashira-type coupling reaction. Graphic abstract