Divergent Synthesis of Chalcogenylated Quinolin-2-ones and Spiro[4,5]trienones via Intramolecular Cyclization of N-Arylpropynamides Mediated by Diselenides/Disulfides and PhICl2

Abstract The reaction of N-arylpropynamides with (dichloroiodo)benzene (PhICl2) and diselenides/disulfides resulted in a divergent synthesis of chalcogenylated quinolinones and spiro[4.5]trienes through intramolecular electrophilic cyclization and chalcogenylation. The chalcogenyl functional group was introduced by an electrophilic reactive organosulfenyl chloride or selenenyl chloride species, generated in situ from the reaction of disulfides/diselenides and PhICl2. Notably, the divergent cyclization pathways were determined by the substituent type on the aniline ring in N-arylpropynamide substrates. Substrates bearing a fluoro, methoxy or trifluoromethoxy group at the para-position of the aniline underwent an alternative spiralization pathway to give the 3-chalcogenylated spiro[4,5]trienones.