Calixradialenes: calixarene derivatives with exocyclic double bonds.

Reaction of dioxocalix[4]arene 7 with MeLi followed by 2-fold elimination of water yielded calixarene 8 possessing exocyclic double bonds at two adjacent bridges. Calixarene 8 exists in tetrachloroethane-d2 solution at rt, as a 2.3:1 mixture of the 1,3-alternate and partial cone conformers.