Synthesis 2018; 50(14): 2727-2740
DOI: 10.1055/s-0037-1610131
paper
© Georg Thieme Verlag Stuttgart · New York

Metal-Free Synthesis of Pyrrolo[1,2-a]quinoxalines Mediated by TEMPO Oxoammonium Salts

Heng-rui Huo
School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan 430074, P. R. of China   Email: gongyf@mail.hust.edu.cn   Email: xytang@hust.edu.cn
,
Xiang-Ying Tang*
School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan 430074, P. R. of China   Email: gongyf@mail.hust.edu.cn   Email: xytang@hust.edu.cn
,
School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan 430074, P. R. of China   Email: gongyf@mail.hust.edu.cn   Email: xytang@hust.edu.cn
› Author Affiliations
This project received financial support from the National Natural Science Foundation of China (21472053, 21172082).
Further Information

Publication History

Received: 29 October 2017

Accepted after revision: 08 April 2018

Publication Date:
13 June 2018 (online)


Abstract

We herein describe a novel TEMPO oxoammonium salt initiated Pictet–Spengler reaction of imines, generated in situ from carbonyl compounds and pyrrole- or indole-containing substrates, to afford 4,5-dihydropyrrolo[1,2-a]quinoxalines or 5,6-dihydroindolo[1,2-a]quin­oxalines in good to excellent yields. Moreover, a one-pot synthesis of a biologically important quinoxaline is achieved via a cyclization–dehydrogenation process using one equivalent of the oxoammonium salt.

Supporting Information