Synthesis 2016; 48(08): 1139-1146
DOI: 10.1055/s-0035-1561334
paper
© Georg Thieme Verlag Stuttgart · New York

Highly Efficient Synthesis of N 1-Substituted 1H-Indazoles by DBU-Catalyzed Aza-Michael Reaction of Indazole with Enones

Jingya Yang*
a   College of Chemistry and Chemical Engineering, Northwest Normal University, Lanzhou 730070, P. R. of China   Email: yangjy@nwnu.edu.cn
,
Yunfen Bao
a   College of Chemistry and Chemical Engineering, Northwest Normal University, Lanzhou 730070, P. R. of China   Email: yangjy@nwnu.edu.cn
,
Hongyan Zhou
b   College of Science, Gansu Agricultural University, Lanzhou 730070, P. R. of China
,
Tianyuan Li
a   College of Chemistry and Chemical Engineering, Northwest Normal University, Lanzhou 730070, P. R. of China   Email: yangjy@nwnu.edu.cn
,
Nana Li
a   College of Chemistry and Chemical Engineering, Northwest Normal University, Lanzhou 730070, P. R. of China   Email: yangjy@nwnu.edu.cn
,
Zheng Li
a   College of Chemistry and Chemical Engineering, Northwest Normal University, Lanzhou 730070, P. R. of China   Email: yangjy@nwnu.edu.cn
› Author Affiliations
Further Information

Publication History

Received: 18 November 2015

Accepted after revision: 30 December 2015

Publication Date:
04 February 2016 (online)


Abstract

1H-Indazoles are important heterocycles as they are a substantial part in many drugs. Here, a DBU-catalyzed aza-Michael reaction of indazole with enones is described. A variety of aromatic and aliphatic enones are well tolerated and afford the corresponding N 1-substituted 1H-indazoles in high to excellent yields with exclusive N 1-regioselectivity. The use of a metal-free catalyst, good substrate tolerance, mild reaction conditions, and high atom economy make this procedure a direct and facile method for the preparation of N 1-substituted 1H-indazoles.

Supporting Information