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

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.

Automated summary

Acylethynylpyrroles can undergo catalyst-free annulation with 1-pyrrolines at room temperature, giving acylmethylenetetrahydrodipyrrolo[1,2-a:1 ' ,2 ' -c]imidazoles. The reaction conditions are simple, with high yields and good E-stereoselectivity of the olefin moiety.