Structurally Simple Benzyl-Type Photolabile Protecting Groups for Direct Release of Alcohols and Carboxylic Acids

Abstract

Structurally simple benzyl-type photolabile protecting groups (PPGs) have been developed to release alcohols and carboxylic acids. Release of two substrates from one PPG chromophore has also been accomplished.

A New Photocage Derived from Fluorene

“…This shows that, also for fluorene‐derived photocages, amino substituents increase the reaction quantum yields and shift the absorbance spectrum to longer wavelengths than those of their methoxy analogues. Similar behavior has been shown for photocages of 7‐ N , N ‐diethylaminocoumarin (DEACM) and 1 . Similar to compound 15 having a more redshifted absorbance than that of monosubstituted 10 , in the case of phenyl substitution, symmetric compound 16 a also has an increased molar absorption coefficient, in comparison with its unsymmetrical analogue, 14 a .…”

“…Reported quantum yields for alcohol release from 1 were 20–26 % (medium‐pressure mercury lamp with a Pyrex filter at λ >280 nm) . Acetate could be released with 8 % quantum yield (at λ =254 nm) from the meta‐N , N ‐dimethylaminobenzyl (DMAMb) photocage .…”

“…Examples of synthetic procedures for selected key compounds are given in the following text. Synthetic details for other compounds can be found in the Supporting Information …”

“…In contrast, Wang et al. demonstrated the remarkable power of the simple 3‐diethylaminobenzyl ( 1 ; Scheme ) chromophore for the release of poor LGs, such as amines and alcohols . This photocage is based on the Zimmerman meta effect and its analogues have been reviewed in detail .…”

Spatial control of flocculation via light

“…[2][3][4] Thus, efficient photochemical reactions are not only the pursuit of organic and polymer chemistry which demand reactions take place under neutral and reagent-free conditions, but are also highly applicable in materials chemistry and biology to mediate processes in a spatially and temporally controlled manner. [5][6][7] In this study, we present a highly efficient photoinitiated flocculation system formed through the trapping of a photogenerated thiobenzaldehyde with polyethylenimines (PEIs). The photocontrolled flocculation has been further demonstrated in the removal of Cu 21 .…”