Anna Paola Pelliccioli, Tomas Pospisil, Petr Klan, Jakob Wirz "2,5-Dimethylphenacyl Esters: A Photoremovable Protecting Group for Phosphates and Sulfonic Acids", Photochem. Photobiol. Sci., 2002, 1, 920 - 923.

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Abstract: Irradiation of 2,5-dimethylphenacyl esters of phosphoric and sulfonic acids releases the corresponding acids in nearly quantitative isolated yields with quantum yields of 68-71 % in methanol and 9-19 % in benzene. In methanol solution the reaction proceeds predominantly via the Z-photoenols, the lifetimes of which (20-25 us) were determined by laser flash photolysis. The chromophore is proposed as an excellent photoremovable protecting group for organic synthesis and biochemistry ("caged compounds").