enynes were developed. A series of cyclopropane-fused hetero-and carbo-bicyclic, tricyclic,
and spiro-tetracyclic compounds were facilely synthesized from a broad scope of 1, 6-
enynes and 2, 6-lutidine N-oxide under mild and metal-free conditions with blue light-
emitting diode light irradiation. The cascade annulation reaction occurs with the
intermediacy of a β-oxyvinyl radical, which is produced from photocatalytically generated …