Understanding palladium catalyzed reactions under mechanochemical conditions

Date
March 20, 2022

Scientists have spent a considerable amount of time and effort designing a pre-catalyst that transforms into the active catalytic species upon entry into the reaction. Scientist typically consider stability and reactivity when designing a pre-catalyst. Often this harmony is difficult to ascertain and require processes that can be detrimental to both human health and the environment. Additionally, the cost of the catalyst is dictated not by the precious metal that conducts the chemistry but by the human labor it takes to create the precursor. We created an active catalyst that is generated in situ under mechanochemical conditions. Here in we report on forming carbon-carbon bonds without the use of solvent. Sonogashira coupling was used as the baseline for the genesis of this project. Previously, the solvent-free Sonogashira coupling of a variety of para-substituted aryl halides with trimethylsilylacetylene or phenylacetylene using a palladium catalyst and copper (0) co-catalyst under mechanochemical conditions was studied. In this current work we seek to use a combination of palladium and copper metal to successfully conduct the solvent-free Sonogashira reaction. We observed high yields when triphenylphosphine was added to the reaction mixture at elevated temperatures. Additionally, it is possible to chemoselectively react one halide over the other based on temperature.

Related Products

Thumbnail for Mechanochemistry, a perfect green chemistry tool
Mechanochemistry, a perfect green chemistry tool
Although the history of mechanochemistry goes back centuries, with the rapid growth of articles about it, it is becoming clear that this once obscure discipline is becoming increasingly mainstream…
Thumbnail for Radical reduction of alkyl and aryl halides under mechanochemical conditions | Poster Board #1417
Radical reduction of alkyl and aryl halides under mechanochemical conditions | Poster Board #1417
Herein, we report a novel method for the solvent-free reduction of alkyl and aryl halides under mechanochemical conditions. Reductions were performed using various alkyl and aryl halides in the presence of different radical initiators and hydrogen atom donors at elevated temperatures…
Thumbnail for Shaking the table on pharmaceutical syntheis: Mechanochemistry in discovery and process
Shaking the table on pharmaceutical syntheis: Mechanochemistry in discovery and process
As the adoption of mechanochemistry has expanded in the academic realm, we've seen work that has enabled greener synthesis of organic moieties, metal organic frameworks, organometallic reagents, polymers, nanoparticles and more…
Thumbnail for Understanding stereoselectivity of Heck cross-coupling reactions under mechanochemical conditions | Poster Board #1033
Understanding stereoselectivity of Heck cross-coupling reactions under mechanochemical conditions | Poster Board #1033
Mechanochemistry is a solventless approach for neat synthetic chemistry; the reaction kinetics are driven by mechanical forces (e.g. sheering, grinding, collisions). This enables the development of new chemical routes. In addition, the absence of solvent lowers generated waste and costs…