Synthesis of indolines and quinoline via cyclization of N-arylsulfonyl-2-allylanilines catalyzed by Brønsted acid

N-Arylsulfonyl-2-allylanilines underwent the intramolecular hydroamination to produce indolines or quinoline in the presence of catalytic amount of triflic acid with good yield. The scope of the reaction was extended to other N-protected aminoalkenes.