A Sunscreen‐Based Photocage for Carbonyl Groups

Abstract

Photolabile protecting groups (PPGs) have been exploited in a wide range of chemical and biological applications, due to their ability to provide spatial and temporal control over light‐triggered activation. In this work, we explore the concept of a new photocage compound based on the commercial UVA/UVB filter oxybenzone (OB; 2‐hydroxy‐4‐methoxybenzophenone) for photoprotection and controlled release of carbonyl groups. The point here is that oxybenzone not only acts as a mere PPG, but also provides, once released, UV photoprotection to the carbonyl derivative. This design points to a possible therapeutic approach to reduce the severe photoadverse effects of drugs containing a carbonyl chromophore.

Eosin Y‐catalyzed reductive homocoupling of para‐quinone methides under visible‐light

“…5,6 The compound IV (Figure 1), owing tetra-arylethane motif, is a sunscreen-based photolabile caged molecule for controlled discharge of carbonyl compounds. 7 Numerous synthetic protocols have been demonstrated so far to access tetra-arylethane derivatives, including dehydroxylative dimerization of benzylic alcohols under visible-light irradiation, 8 nickel/oxo-rhenium-catalyzed and ReIO 2 (PPh 3 ) 2 -promoted reductive coupling of secondary benzylic alcohols, [9][10][11] dehalogenative radical coupling of secondary benzylic halides, [12][13][14][15][16] dehydrogenative homocoupling of benzylic C-H bonds under photoredox catalysis, 17 photoderiven decarboxylative radical dimerization of diphenyl acetic acid, 18 hydrogenation of tetraphenylethylene using a metal-based amide catalyst, 19 nickel-catalyzed and hydrazine-mediated deoxygenative coupling of ketones 20 and reductive coupling of aromatic ketones under photoredox conditions. 21,22 Recently, Tang, Cai and coworkers have been described a visible lightmediated potassium-modified carbon nitride (CN-K) catalyzed reductive dimerization of p-quinone methides (p-QMs) to access tetra-arylethane derivatives.…”

“…Similarly, 1,1,2,2‐tetraphenyl‐1,2‐ethanediol III (Figure 1) is utilized as a thermal radical initiator and a thermal iniferter in the radical polymerization process 5,6 . The compound IV (Figure 1), owing tetra‐arylethane motif, is a sunscreen‐based photo‐labile caged molecule for controlled discharge of carbonyl compounds 7 …”