Synthesis of Azulen-1-yl Ketones via Oxidative Cleavage of C–C Multiple Bonds in <i>N</i>‑Sulfonyl Enamides and 1‑Alkynes under Air and Natural Sunlight

Abstract

A synthetic method to prepare azulen-1-yl ketones was developed via oxidative cleavage of the C–C double bond in the reaction of easily obtainable <i>N</i>-sulfonyl enamides with Cs₂CO₃ under air and natural sunlight and in the absence of a photosensitizer. Oxidative cleavage of C–C triple bonds was also demonstrated for the synthesis of azulen-1-yl ketones via a tandem Cu-catalyzed [3 + 2] cycloaddition, Rh-catalyzed arylation, photooxygenation, and ring-opening reaction in one pot under air and natural sunlight