Synthesis of quinolines via sequential addition and I 2 -mediated desulfurative cyclization.

An efficient one-pot approach for the synthesis of quinolines from o -aminothiophenol and 1,3-ynone under mild conditions is disclosed. With the aid of ESI-MS analysis and parallel experiments, a three-step mechanism is proposed-a two-step Michael addition-cyclization condensation step leading to intermediate 1,5-benzothiazepine catalyzed by zirconocene amino acid complex Cp 2 Zr(η 1 -C 9 H 10 NO 2 ) 2 , followed by I 2 -mediated desulfurative step.