Bismuth(III) Chloride-Catalyzed Intramolecular Hetero Diels-Alder Reaction: Application to the Synthesis of Tetrahydrochromano[4,3-b]quinoline Derivatives

Intramolecular [4+2] cycloaddition reaction of aldimines derived from aromatic amines and O-allyl derivatives of salicylic aldehydes was efficiently catalyzed by BiCl3 to afford the corresponding tetrahydrochromano[4,3-b]quinolines in excellent yields. The products are isolated as 1:1 mixture of diastereoisomers.