Visible‐Light‐Mediated Synthesis of 1‐Oxa‐4‐aza‐spiro Oxazolines by Spiroannulation of Quinones with Vinyl Azides

A simple and efficient method has been developed to synthesize 1‐oxa‐4‐aza‐spirooxazolines. The reaction was carried out at room temperature using rose bengal as an organic photoredox catalyst and blue LED as a light source. It was observed that quinones underwent spiroannulation reaction with vinyl azide on C−O double bond instead of C−C double bond through which various corresponding 1‐oxa‐4‐aza‐spirooxazolines have been synthesized in good to excellent yields. An unusual synthesis of 1‐oxa‐4‐aza‐spirooxazoline derivatives has been reported by the visible light‐mediated spiroannulation reaction of quinones with vinyl azides. A plausible mechanism was proposed based on some control experiments. Morpholine and indole‐substituted spiro‐products were also obtained as further functionalization of the main synthesized products.