title: Calixradialenes: calixarene derivatives with exocyclic double bonds.
abstract: 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. Keto[n]calixarenes (n = 5, 6) were prepared via hydrolysis of the bromocalixarenes 11 and 12, followed by CrO3 oxidation of the respective hydroxymethylene derivatives. Addition of MeLi to the ketocalix[n]arenes (n = 4, 5 and 6) followed by elimination of water yielded the corresponding calix[n]radialenes. Calix[5]- and calix[6]radialenes adopt in the crystal irregular alternate (i.e., noncone) conformations.
authors.affiliation: Institute of Chemistry, The Hebrew University of Jerusalem , Jerusalem 91904, Israel .
authors.forename: David
authors.initials: D
authors.lastname: Poms
authors.forename: Norbert
authors.initials: N
authors.lastname: Itzhak
authors.forename: Lev
authors.initials: L
authors.lastname: Kuno
authors.forename: Silvio E
authors.initials: SE
authors.lastname: Biali