Synthesis of mono-functionalized S-diazocines via intramolecular Baeyer-Mills reactions.

Herein we report a reliable method to synthesize mono-functionalized S-diazocines in reproducible yields via intramolecular Baeyer-Mills reactions. Diazocines exhibit excellent photoswitchable properties. As opposed to azobenzenes they are more stable in their configuration. Particularly in photopharmacology mono-functionalized diazocines should be potentially useful and superior to the frequently used azobenzenes because the sterically more demanding configuration should be inactive, and the slender configuration should fit in a tight binding pocket of a receptor. Hence, it should be possible to administer the stabile inactive compound and switch it on at the site of illness with visible light. To date only a limited number of diazocine derivatives have been published of which most are symmetrically functionalized. Using the Baeyer-Mills reaction for the synthesis of diazocines opens a novel and convenient access to unsymmetrically substituted diazocines.