A Brønsted acid catalyzed tandem reaction for the diastereoselective synthesis of cyclobuta-fused tetrahydroquinoline carboxylic esters.

A novel Bronsted acid catalyzed tandem reaction provides highly functionalized cyclobuta-fused tetrahydroquinoline carboxylic esters from anilines and 2-alkylenecyclobutanones and in good to high yield. During the reaction a diastereoselective dynamic kinetic resolution is achieved, resulting in the formation of three contiguous stereocenters with high stereoselectivity.