Synthesis of Pyrrolo[1,2-a]quinoxalines via Gold(I)-Mediated Cascade Reactions

Guannan Liu, Yu Zhou, Daizong Lin, Jinfang Wang, Lei Zhang, Hualiang Jiang, Hong Liu

ABSTRACT: In this study, we developed an efficient tandem process of hydroamination and hydroarylation using a gold catalyst to enable and study the reactions between pyrrole-substituted anilines and alkynes. The gold(I)-catalyzed reactions were achieved in toluene at 80 C over a reaction time of 16 h. These reactions are applicable to a variety of aromatic amino compounds and both the terminal and internal alkynes. Substituted pyrrolo[1,2-a]quinoxalines were obtained in moderate to excellent yields. A presumed mechanism involving intermolecular CN bond formation and intramolecular nucleophilic reaction via a cationic gold complex has been proposed on the basis of the deuterium labeling studies.

KEYWORDS: gold-catalyst, cascade reaction, hydroamination, hydroarylation