Visible Light-Induced Synthetic Approach for Selenylative Spirocyclization of N-Aryl Alkynamides with Molecular Oxygen as Oxidant

A visible light-induced (blue LED) radical cascade has been devised to effect selenylative spirocyclization of N-aryl alkynamides at room temperature under oxygen atmosphere and without the aid of external photocatalyst. The protocol is operationally simple, scalable, and offers clean synthesis of 3-selenospiro[4,5]trienones in high yields (up to 92%). A novel spiro-ring-opening strategy has also been accomplished to access fully substituted acryl amides. (Figure presented.).