Sustainable Approach to Waste-Minimized Sonogashira Cross-Coupling Reaction Based on Recoverable/Reusable Heterogeneous Catalytic/Base System and Acetonitrile Azeotrope

Abstract

In this contribution, we present a chemically efficient and sustainable protocol for the palladium-catalyzed copper-free Sonogashira cross-coupling reaction, based on the use of a heterogeneous catalytic system. This consists in the combination of a palladium catalyst on highly cross-linked thiazolidine network on silica and a polystyrene-supported base. The solid catalyst/base system acts as a palladium scavenger avoiding leaching of the metal and consequent product contamination. The reaction can be conducted in safe and easily recoverable acetonitrile/water azeotrope as reaction medium. This proved to be an efficient greener alternative to the classic toxic aprotic media commonly used in cross-coupling reaction, such as DMF and NMP. Acetonitrile/water azeotrope could be easily recovered and reused allowing the minimization of waste production. Our approach, based on the use of both a supported base and a supported catalyst, has proven to be efficient for the waste reduction, as proved by the low E-factor values achieved

Cost-effective sustainable-engineering of CH3NH3PbI3 perovskite solar cells through slicing and restacking of 2D layers

“…In addition, ACN provides safer reaction medium, better life cycle and lower waste-handling issues, which leads to sustainable PSC fabrication. [19,20] By employing the sustainable solvent system, we fabricated lowtemperature processed cell with a conversion efficiency of 15.9%, which was similar to that of PSC fabricated using high temperature annealing process. …”

Immobilized Palladium Nanoparticles on Zirconium Carboxy-Aminophosphonates Nanosheets as an Efficient Recoverable Heterogeneous Catalyst for Suzuki–Miyaura and Heck Coupling

“…Lately, we have been interested in the development of novel solid metal catalysts to be used in safe reaction media for the design of environmentally-sustainable processes [15,19,34,[36][37][38].…”

Solid-Supported Palladium Catalysts in Sonogashira Reactions: Recent Developments

“…Moreover, the radical oligomerization of a bisvinylthiazolium salt in the presence of mercapto-functionalized mesoporous silica SBA15 gave a material that was able to immobilize palladium atoms. The generated supported catalyst 48 was used in the Sonogashira coupling of several phenylacetylene derivatives with different aromatic iodides in a reusable acetonitrile/water azeotrope as reaction medium [87]. The reaction was carried out using N-methylpiperazine as a base or PS-supported piperazine, affording the expected products in similar yields, although longer reaction times were required when the heterogeneous base was used.…”