NCN–Pincer–Pd Complex as Catalyst for the Hiyama Reaction in Biomass-Derived Solvents

Abstract

A NCN–pincer–Pd complex has been synthesized and applied to Hiyama-type cross-coupling reactions between aryl halides and different types of organosilanes using neoteric solvents. This report constitutes a green approach to cross-coupling reactions since the reagents employed are stable and nontoxic. The solvents used (deep eutectic solvents based on choline chloride or glycerol) are also biodegradable, nontoxic, nonflammable, and biorenewable. Furthermore, the catalytic system can be recycled, allowing us to perform the reaction for at least three cycles without adding more catalyst or solvent, increasing the value of the process from an economical and environmental point of view. The effect of these solvents on the catalytic activity has been studied. Finally, a gram-scale reaction has also been tested affording biaryl products in high yields and purity by a simple liquid–liquid extraction, without the need of aqueous workup or chromatographic steps, proving the applicability of this approach in a sustainable industrial scale.