Direct Dearomatization of Quinoline/Isoquinoline Ammonium Halides to Construct N‐Substituted Tetrahydroquinolines and Tetrahydroisoquinolines

Abstract Dearomatization of quinoline/isoquinoline quaternary ammonium salts to synthesize valuable tetrahydroquinolines was firstly reported. Under this method, we used phenylsilane as a reducing agent to prepare a series of tetrahydroquinoline and tetrahydroisoquinoline derivatives conveniently and quickly in moderate to good yields. This method showed good functional group tolerance, wide substrate range, mild reaction conditions and simple operation.