Cascade nitration/cyclization of 1,7-enynes with tBuONO and H2O: one-pot self-assembly of pyrrolo[4,3,2-de]quinolinones.

Here we describe the one-pot construction of the pyrrolo[4,3,2-de]quinolinone scaffold by a cascade nitration/cyclization sequence of 1,7-enynes with tBuONO and H2O. The cascade proceeds through alkene nitration, 1,7-enyne 6-exo-trig cyclization, C-H nitrations, and redox cyclization, and exhibits excellent functional group tolerance. The mechanism was investigated using in situ high-resolution mass spectrometry (HR-MS).