Synthesis of (-)-viriditoxin: a 6,6'-binaphthopyran-2-one that targets the bacterial cell division protein FtsZ.

Abstract

The inhibition of bacterial cell division offers a new approach to controlling resistant bacterial infections.[1, 2] FtsZ is a protein of central importance to cell division that is often described as the prokaryotic homolog of tubulin because of the structural similarity of these two proteins, in spite of low sequence homology.[3–5] Both proteins undergo GTP-driven oligomerization and the active sites of both proteins are similar. Tubulin forms microtubules in the bipolar spindle assembly, which mediates chromosome separation in eukaryotes. FtsZ oligomerizes at midcell during bacterial cell division to form the Z-ring, which constricts to induce septation. Inhibition of FtsZ has been validated as a potential new therapeutic strategy for fighting resistant infections, including MRSA.[6–8] In stark contrast to tubulin, few FtsZ-targeting natural products are known and no information regarding the molecular basis of their inhibition of FtsZ has been documented.[9–12] The development of efficient syntheses for FtsZ-targeting natural products will enable elucidation of their mechanisms of inhibition and enable further development of this target. This communication describes the synthesis of viriditoxin, one the most potent FtsZ-targeting natural products and the first 6,6'-binapthopyranone to be synthesized.[13]