Programmed Polyene Cyclization Enabled by Chromophore Disruption.

A new polyene cyclization strategy exploiting ß-ionyl derivatives was developed. Photoinduced deconjugation of the extended π-system within these chromophores unveils a contrathermodynamic polyene that engages in a Heck bicyclization to afford [4.4.1]-propellanes. This cascade improves upon the limited regioselectivity achieved using existing biomimetic tactics and tolerates both electron-rich and electron-deficient (hetero)aryl groups. The utility of this approach was demonstrated with the diverted total synthesis of taxodione and salviasperanol, two isomeric abietane diterpenes that were previously inaccessible along the same synthetic pathway.

A sticky situation for targeted cancer therapy.

In this issue of Cell Chemical Biology, Andlovic et al.1 unravel how certain fusicoccin toxins synergize with interferon-α to kill cancer cells. The results suggest that fusicoccins potentiate apoptosis by "sticking together" 14-3-3 protein-protein interactions.

Pyridazine N-Oxides as Photoactivatable Surrogates for Reactive Oxygen Species.

A method for the photoinduced evolution of atomic oxygen from pyridazine N-oxides was developed. This underexplored oxygen allotrope mediates arene C-H oxidation within complex, polyfunctional molecules. A water-soluble pyridazine N-oxide was also developed and shown to promote photoinduced DNA cleavage in aqueous solution. Taken together, these studies highlight the utility of pyridazine N-oxides as photoactivatable O(3P) precursors for applications in organic synthesis and chemical biology.