Concise Synthesis of 4‐Arylquinolines via Intramolecular Cyclization of Allylamines and Ketones

The intramolecular cyclization of allylamines and ketones was achieved in the presence of potassium tert‐butoxide and N,N‐dimethylformamide. A series of 4‐arylquinolines was prepared in good yields. The reaction could be accomplished at room temperature using only a substoichiometric amount of potassium tert‐butoxide. On the other hand, the reaction of the structurally analogous allyl ethers afforded diverse products. The reaction may proceed via the rearrangement of α‐aminoallyl radicals and the generation of nucleophilic enamine intermediates. This finding represents a new strategy for the synthesis of quinoline derivatives from readily available 2‐(allylamino)phenyl ketones.