Synthesis of hindered spiro-oxindoles by photolysis of 1-(1- alkenyl)benzotriazoles

Article abstract of DOI:10.1016/S0040-4020(99)00691-2

Photolysis of 1-(1-alkoxy-1-alkenyl)benzotriazoles gives moderate yields of 2-alkoxy-indolenines, which can be hydrolysed to oxindoles. A side reaction leads to the formation of imino-oxetanes. The formation of the 2- alkoxy-indolenines is quite insensitive to steric hindrance at the reacting centres.