REACTION OF ELECTRON-RICH ALKENES WITH ANILINES AND FORMALDEHYDE - SYNTHESES OF TETRAHYDROQUINOLINES

A one-pot synthesis has been established of tetrahydroquinolines based upon reaction of aromatic amines and formaldehyde with electron rich alkenes such as styrene, alpha-methylstyrene, 1-phenylcyclohexene and 3,4-dihydro-2H-pyran. The isolation of alcohols as additional products from reactions conducted in acetonitrile containing trifluoroacetic a cid, and the demonstration that these alcohols reacted further under s imilar reaction conditions to give efficiently cyclised products indic ates that the cyclisations reported in this paper are not concerted. T he importance is discussed of similar multi-step processes in the cata lysed addition of electron rich alkenes to preformed imines.