Applied Photochemistry – Light Controlled Perfume Release

Abstract

Ambient light is one of the most suitable available trigger conditions for the release of covalently bound volatile odorants in home- and laundry-care applications. We report on three complementary classes of light-cleavable fragrance precursors, covering the controlled release of odorants with a wide range of functional groups. o-Hydroxy cinnamates 1 undergo a UV-induced double bond isomerization followed by transesterification to release coumarin and a fragrance alcohol of choice. ?-Alkoxyacetophenones 10 and ?,?-dialkoxyacetophenones 12 undergo Norrish type II fragmentations upon UV-irradiation, thereby releasing one or two equivalents of fragrant aldehydes, respectively. Finally, photoexcited Xanthenoic esters 22 undergo fragmentation to release reactive acyl radicals, which further cyclize onto internal olefins to form perfumery lactones of various ring sizes.