Metal-free nitro/azido cyclization of 1-acryloyl-2-cyanoindoles to access NO2/N3-featuring pyrrolo[1,2-a] indolediones

Abstract

An H₂O/heating or [bis(trifluoroacetoxy)iodo]benzene promoted radical cascade nitro/azide cyclization of 1-acryloyl-2-cyanoindoles with tert-butyl nitrite/azidotrimethylsilane was accomplished, which offered a series of nitro/azide-featuring pyrrolo[1,2-a]indolediones in good yields. Meanwhile, some scale-up experiments and substituent transformations were performed to test the synthetic value. In addition, the corresponding radical intermediates were successfully detected by HRMS to support the possible reaction pathway.