AlCl₃‑Catalyzed Intramolecular Cyclization of <i>N</i>‑Arylpropynamides with <i>N</i>‑Sulfanylsuccinimides: Divergent Synthesis of 3‑Sulfenyl Quinolin-2-ones and Azaspiro[4,5]trienones

Switchable ortho/ipso-cyclization of N-arylpropynamides induced with N-sulfanylsuccinimides as general sulfur reagents is reported. In the presence of MeOH, para-fluoro N-arylpropynamides exclusively undergo the ipso-cyclization to give 3-sulfenyl azaspiro­[4,5]­trienones. Two kinds of bioactive heterocycles, benzothieno-[3,2-b]­quinoline and -[2,3-c]­quinolone, have been directly and efficiently prepared from the corresponding sulfenylated products.本文报道了以N-硫代琥珀酰亚胺作为通用硫试剂，诱导N-芳基丙炔酰胺发生可切换邻位/ipso-环化（ortho/ipso-cyclization）的反应。在甲醇（MeOH）存在条件下，对位氟取代的N-芳基丙炔酰胺专一性地发生ipso-环化，生成3-硫代氮杂螺[4,5]三烯酮。研究人员可从相应的硫代产物中，直接高效地制备两种具有生物活性的杂环化合物：苯并噻吩并[3,2-b]喹啉与苯并噻吩并[2,3-c]喹啉酮。