Visible light-promoted metal-free intramolecular cross dehydrogenative coupling approach to 1,3-oxazines

Abstract Visible light promoted intramolecular cross dehydrogenative coupling of 1-aminoalkyl-2-naphthols to 1,3-oxazines is developed. Green LED lamp was used as the light source and eosin Y functions as photoredox catalyst. The reaction was carried out in the absence of transition-metal photoredox catalysts and additional additives. Aerial oxygen was used as the terminal oxidant. The method offers clean and efficient synthesis of these important classes of heterocycles.