Synthesis of tetrahydroquinolines and quinoline derivatives through the Lewis acid catalysed Povarov reaction: A comparative study between multi step and multi-component methods

In this work, we have synthesised a new disubstituted tetrahydroquinolines by the Povarov [4+2] cycloaddition reaction between imines derivatives and an electron-rich olefin such as vinyl ethers. These reactions were carried out in the presence of different acid catalysts in its two versions, multi-step reaction starting with imine synthesis and multi-component reaction in which the imine is formed in situ. The reactivity of the cycloaddition reaction is directly attributed to the nature of the reagents, the used synthetic strategy, in which the obtained yield is found in the case of multi-step reactions lower than that in the multi-component reaction one. Additionally, the multi-step reactions are faster kinetically in comparison with that of the multi-component one. The nature of the catalyst directly increases the rate and enhances the yield of the reactions.