Photochemical rearrangement of calix[4]arene-derived bis(spirodienones): formation of a new macrocycle.

Bis(spirodienones) of calix[4]arene undergo a facile photochemical rearrangement leading to a new macrocycle having a spirocyclic cyclopentenone-THF unit, a trisubstituted phenol, and a benzofuran moiety. The macrocyclic ring system has a 14-membered irregular cavity and resembles a partial bowl in the solid state.