Synthesis of Substituted Quinolines by the Electrophilic Cyclization of n-(2-Alkynyl)anilines.

Abstract A wide variety of substituted quinolines are readily synthesized under mild reaction conditions by the 6- endo - dig electrophilic cyclization of N -(2-alkynyl)anilines by ICl, I 2 , Br 2 , PhSeBr, and p -O 2 NC 6 H 4 SCl. The reaction affords 3-halogen-, selenium- and sulfur-containing quinolines in moderate to good yields in the presence of various functional groups. Analogous quinolines bearing a hydrogen in the 3-position have been synthesized by the Hg(OTf) 2 -catalyzed ring closure of these same alkynylanilines.