This paper describes a highly efficient [3 + 2] reaction between 3-vinylindoles and 3-indolylmethanols. Novel 2,3-bisindolylmethanes were prepared as single diastereoisomers in high yields with the promotion of 1 mol% 2-hydroxy-3,5-dinitrobenzoic acid.
![Graphical abstract: Highly efficient [3 + 2] reaction of 3-vinylindoles with 3-indolylmethanols by Brønsted-acid catalysis](http://hg.y866.cn/compound/lib/scimg/usr/1/C3RA47056C.jpg)