Catalyst-Free Annulation of Acylethynylpyrroles with 1-Pyrrolines: A Straightforward Access to Tetrahydrodipyrrolo[1,2- a:1',2'- c]imidazoles

J Org Chem. 2022 Aug 5;87(15):9518-9531. doi: 10.1021/acs.joc.2c00476. Epub 2022 Jul 18.

Abstract

Acylethynylpyrroles undergo facile (rt, MeCN or MeOH, 24-72 h) catalyst-free annulation with 1-pyrrolines to afford acylmethylenetetrahydrodipyrrolo[1,2-a:1',2'-c]imidazoles in up to 93% yield and 90% E-stereoselectivity of the olefin moiety.