I2-catalyzed base-free cyclization of 3-homoallylquinoline-2-thiones: facile synthesis of tetracyclic, furothiopyrano [2, 3-b] quinolines
M Asthana, N Sharma, R Kumar, JB Singh, RM Singh - Tetrahedron Letters, 2014 - Elsevier
I 2-catalyzed base-free reactions of 3-homoallylquinoline-2-thiones have been described for
the synthesis of tetracyclic quinolines, tetrahydrofuro [2′, 4′: 4, 6] thiopyrano [2, 3-b]
quinolines in excellent yields. Similarly, I 2-catalyzed reactions could proceed to tricyclic
quinolines from hydroxyl group protected 3-homoallylquinoline-2-thiones. However,
deprotection of group in tricyclic quinoline with HI again transformed into tetracyclic
quinoline. The sulfonium salt intermediate has been proposed to explain these reactions.
the synthesis of tetracyclic quinolines, tetrahydrofuro [2′, 4′: 4, 6] thiopyrano [2, 3-b]
quinolines in excellent yields. Similarly, I 2-catalyzed reactions could proceed to tricyclic
quinolines from hydroxyl group protected 3-homoallylquinoline-2-thiones. However,
deprotection of group in tricyclic quinoline with HI again transformed into tetracyclic
quinoline. The sulfonium salt intermediate has been proposed to explain these reactions.