Saccharin‐catalyzed multicomponent cascade reactions for the synthesis of 1,2,3,4,6‐pentasubstituted piperidines

Abstract A convenient and efficient method is developed for the synthesis of 1,2,3,4,6‐pentasubstituted piperidines via a three‐component, one‐pot domino reaction of β‐ketoesters, aromatic aldehydes, and aromatic amines in the presence of a catalytic amount of saccharin in methanol at 40°C. The desired piperidines could be easily collected through simple filtration with excellent diastereoselectivities.