Total synthesis of pterosines B and C via a photochemical key step

A total synthesis of pterosines B and C is reported. Starting with a fourfold substituted benzene derivative, the introduction of the remaining substituents is mainly based on Sonogashira couplings followed by different transformations of the ethyne moiety. The key step is a photochemical ring-closure of an alpha-mesyloxy ketone forming the 1-indanone skeleton.