Indolizines Enabling Rapid Uncaging of Alcohols and Carboxylic Acids by Red Light-Induced Photooxidation

The irradiation of red light-emitting-diode light (λ = 660 nm) to 3-acyl-2-methoxyindolizines in the presence of a catalytic amount of methylene blue triggered the photooxidation of the indolizine ring, resulting in a nearly quantitative release of alcohols or carboxylic acids within a few minutes. The method was applicable for photouncaging various functional molecules such as a carboxylic anticancer drug and a phenolic fluorescent dye from the corresponding indolizine conjugates, including an insulin–indolizine–dye conjugate.