Iodine-Promoted Formal [5+1] Annulation of 2-Vinylanilines and Thiurams: A Facile Approach to the Synthesis of 2-Aminoquinolines

Abstract Quinolines, especially 2-aminoquinolines, are highly important heterocycles in medicinal chemistry. 2-Aminoquinolines can be synthesized by stepwise construction of the quinoline ring followed by additional amination; however, this protocol is cumbersome. Here, we describe a [5+1]-cyclization of 2-vinylanilines with tetraalkylthiuram disulfides in the presence of iodine and copper(II) triflate. This reaction directly employs readily available and low-cost thiuram as both a C1 synthon and a nitrogen source, providing a facile approach to one-step syntheses of a variety of 2-aminoquinolines in good to excellent yields.