Zinc catalyzed, microwave irradiated Sonogashira reaction by Sodium Aluminate (NaAlO₂) as a base in water: A Green entente

Abstract

The Sonogashira reaction (SNR) is undeniably the most applicable and efficient scheme in chemical synthesis, which involves the formation of C-C bonds by cross-coupling reaction (CCR) with terminal alkyne and halides of aryl or vinyl system. Typically, Pd serves as a catalyst for this reaction, with Cu serving as a co-catalysts and bases can be phosphine or amine. The applicability of such reactions lies in synthesizing medicines, heterocycles, and imitators in products of nature, biologically active complex compounds, nanomaterials, and other organic compounds. In this research, we could implement the SNR effectively without the need for the chemicals mentioned above reagents by using sodium aluminate (NaAlO2) as a base and catalyst as zinc under microwave irradiation (MWR) in water. The approach bears the potential to be in coherence with the principles of green chemistry and make reactions more atom-friendly. In order to achieve inexpensive and eco-friendly energy conditions, we developed one of the straightforward, concise, convergent protocols for sequential coupling and cyclization from Acetylenic species of quinoline-8-ol synthesized in situ by the CCR under MWR. Furthermore, the reaction used zinc as a catalyst and NaAlO2 as a base in the aqueous phase.