In parallel to the discovery of new reactions there is also a need to develop a more “green attitude”. We, synthetic chemists are often too busy focused on our target molecules to pay much attention to the “costs” of our achievements. Synthesis frequently requires the use of relatively expensive and toxic transition-metals, large amounts of solvents and additives that lead to the generation of waste along with the desired products.
Going green also has an impact in economy. Industry expends important amounts of time (which means money) and money trying to remove metal catalysts and solvents. Some transition metals are toxic even at very low concentrations and that is obviously undesirable for pharma industry. Small amounts of metals can have an undesired influence in the colour or properties of an organic polymer.
It is important to invest time and resources in the development of metal free methodologies. In this post I want to highlight the work published in Green Chemistry by Wei Yi and co-workers toward the metal and solvent free synthesis of benzene and pyridine derivatives.
Pyridine and benzene derivatives are commonly found in organic molecules with interest in material or medicinal sciences. This new methodology describes the synthesis of benzene and pyridine derivatives from ready available ketones and amines using HOTf as catalyst. Wei Yi and co-workers remove any stochiometric or catalytic amounts of metals from the equation together with solvents.The reaction is performed in one pot with no need of other oxidants than air and features excellent yields, chemoselectivity and functional group tolerance.
If you want to know more why don’t you take a look to the original paper:
HOTf-Catalyzed Sustainable One-Pot Synthesis of Benzene and Pyridine Derivatives under Solvent-free Conditions. Xu Zhang, Zhiqiang Wang, Kun Xu, Yuquan Feng, Wei Zhao, Xuefeng Xu, Yanlei Yan and Wei Yib. Green Chem., 2016, Advance Article DOI: 10.1039/C5GC02747K
And my advice to all is that you consider GO GREEN: