Chiral Photocages Based on Phthalimide Photochemistry

A new class of photoremovable protecting groups, based on a photoinduced decarboxylation reaction coupled with the elimination of the caged molecule, is described for 2-phthalimido-3-hydroxy-propionate derivatives. When derived from enantiopure N-phthaloyl- serine or threonine, the chirality of the starting amino acid is transmitted to the protected (caged) molecule. These photocages possess good properties for their use in biological systems, and the introduction of chirality opens new possibilities for the study of diastereoselective photochemistry and stereodifferentiation processes involving the release of the caged molecule.