Anthracen-9-ylmethylene-(4-methoxyphenyl)amine: efficient promoter for silver-free palladium-catalyzed aerobic oxidative Sonogashira reactions

摘要

An efficient protocol for the synthesis of unsymmetrical substituted diarylacetylenes by the C(sp(2))-C(sp) cross-coupling reactions of substituted phenylacetylenes and electronically different arylboronic acids has been developed. Anthracen-9-ylmethylene-(4-methoxyphenyl)amine was employed as an efficient promoter in this Pd(OAc)(2)-catalyzed oxidative Sonogashira reaction in air in the absence of silver salt under optimized reaction conditions. The impact of reaction parameters such as solvent, base, reaction temperature and time in this silver-free aerobic oxidative Sonogashira cross-coupling reaction was also evaluated. Electron-deficient phenylacetylenes, which are sluggish coupling partners in the traditional Sonogashira reaction, underwent coupling in this protocol. The catalytic system is inexpensive, effortlessly attainable and highly flexible for functionalized phenylacetylenes and arylboronic acids. Graphic abstract