Beyond a Protecting Reagent: DMAP-Catalyzed Cyclization of Boc-Anhydride with 2‑Alkenylanilines

A novel rapid synthesis of quinolines from 2-alkenylanilines has been described; the reaction involves an unexpected DMAP-catalyzed cyclization of 2-alkenylanilines with di-tert-butyl dicarbonate (Boc2O, 2.0 equiv), and a series of tert-butyl quinolin-2-yl carbonate with various functional groups have been synthesized in good yields under mild conditions. Furthermore, the tert-butyl quinolin-2-yl carbonate can be easily converted into corresponding quinolinones and 2-(pseudo)­haloquinolines.