Three-component reactions of nitroarenes, aldehydes, and phenylacetylene in the presence of indium in dilute hydrochloric acid produce the corresponding quinoline derivatives under reflux. The conversion in this one-potsynthesis involves the following steps: (i) reduction of the nitroarenes to anilines, (ii) coupling of the anilines, aldehydes, and phenylacetylene, (iii) cyclization of the resulting
The reaction of imines with alkynes and alkenes, in the presence of 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ), to give quinoline derivatives is described. The mechanism of the annulation is discussed, and evidence supporting a non-concerted pathway, at least when the alkene is butyl vinyl ether, is reported. Preliminary information is also given about solid adducts of imines with DDQ, which do
CF3SO3H-catalyzed [4+2] aza Diels–Alder reaction of aldimines with silyl enol ethers, and subsequent in situ oxidation furnished quinoline derivatives in good to excellent yields, wherein use of CF3SO3H as a Brønsted acid is critical for the cyclization reaction.