Brønsted acid-catalysed allylic amination of 1-(2-aminoaryl)prop-2-en-1-ols to 1,2-dihydroquinolines

A highly efficient synthetic method to prepare 1,2-dihydroquinolines that relies on trifluoromethanesulfonic acid (TfOH)-catalysed allylic amination of 1-(2-aminoaryl)prop-2-en-1-ols is described. Achieved at a catalyst loading of 0.01 mol-% under mild conditions at room temperature, the reaction was found to be robust, with a wide range of substitution patterns tolerated. The corresponding N-heterocyclic adducts were obtained in good to excellent yields of 45-93 %.