Modification of Photochemical Reactivity by Cyclodextrin Complexation: Product Selectivity in Photo-Fries Rearrangement

Article abstract of DOI:10.1016/S0040-4020(01)86094-4

Cyclodextrin encapsulation, both in the solid state and in aqueous solution brings about a remarkable regulation of the photo-Fries rearrangement of phenyl esters and anilides.In comparison to the non-selective mixture of ortho and para-rearranged isomers along with the deacylated product obtained in organic solvents, the solid β-cyclodextrin complexes of unsubstituted esters and anilides show a remarkable 'ortho-selectivity'.An impressive 'regio-selectivity' among the two ortho-rearranged isomers is observed for meta-substituted esters and anilides upon irradiation as β-cyclodextrin complexes.Specific orientations of the unsubstituted and meta-substituted esters and anilides in the β-cyclodextrin cavity are suggested to be responsible for the observed selectivity.