Synthesis of DNA Interstrand Cross‐Links Using a Photocaged Nucleobase

The missing linking : BCNU is a chemotherapy drug that generates an ethylene bridge between N 1 of deoxyguanosine and N 3 of deoxycytidine. No synthesis of a DNA containing this moiety has been reported until now. A new strategy uses a photocaged nucleobase that, when released, generates a highly reactive intermediate which cross‐links the opposing DNA strand in a manner analogous to BCNU (see scheme, NBOC= ortho ‐nitrobenzyloxycarbonyl).