Wavelength-selective uncaging of dA and dC residues.

Nitrodibenzofuran (NDBF) groups are used as photolabile "caging" groups to temporarily mask the Watson-Crick interaction of dA and dC residues. They show improved masking capabilities and are photodeprotected 12 times more efficiently than 1-(o-nitrophenyl)-ethyl (NPE) caging groups in these positions. Furthermore, NDBF groups can be removed wavelength-selectively in the presence of NPE groups. This will allow more complex (un)caging strategies of oligonucleotides--beyond the usual irreversible triggering.