Modification of photochemical reactivity by cyclodextrin complexalion: product selectivity in photo-fries rearrangement

✍ Scribed by M.S. Syamala; B.Nageswer Rao; V. Ramamurthy

• Publisher: Elsevier Science
• Year: 1988
• Tongue: French
• Weight: 624 KB
• Volume: 44
• Category: Article
• ISSN: 0040-4020
• DOI: 10.1016/s0040-4020(01)86094-4

✦ Synopsis

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 nonselective mixture of ortho and para-rearranged isomers along with the deacylated product obtained in organic solvents, the solid 6-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 6-cyclodextrin complexes. Specific orientations of the unsubstituted and meta-substituted esters and anilides in the f3-cyclodextrin cavity are suggested to be responsible for the observed selectivity.