Photorelease of phosphates: Mild methods for protecting phosphate derivatives

• Sanjeewa N. Senadheera,
• Abraham L. Yousef and
• Richard S. Givens

Beilstein J. Org. Chem. 2014, 10, 2038–2054, doi:10.3762/bjoc.10.212

• photo-Favorskii rearrangement concomitant with ligand release. The combination of these features shifts and extends the chromophore, exhibiting a more intense, broader absorption band closer to the visible region, making the PPG more accessible for photodeprotection. Thus, elaborating the two motifs by

• , however, the chromophore did not undergo the photo-Favorskii rearrangement, forming only the reduction product 2-acetyl-6-hydroxynaphthalene (6) in addition to other unidentified photoproducts (Scheme 5). These results paralleled our observations for 14a,b in aq MeCN. Finally, photolysis of 5,8-BQA

• ) in low yield and is absent of any chromophore rearrangement. It is surprising that 2,6-HNA DEP (10) and Wan’s 1,5-HNA acetate 27 [19] do not undergo a photo-Favorskii rearrangement. In the case of 27, Wan suggested that the lack of reactivity may have arisen from factors such as a lower excited state