title: Synthesis and characterization of new chiral calix[4]arenes.
abstract: The unique chiral calixarenes were successfully synthesized by the following two methods: the Williamson ether synthesis and a stepwise ether cleavage with a mild Lewis acid. The high regioselectivity is recognized by the latter stepwise method. The ionophores having oligoethylene glycol unit efficiently extracted larger alkali metal ions like K+, Rb+, and Cs+ than smaller ones like Li+ and Na+. Their ion selectivity apparently changed by the chain length of crown ether. All racemates obtained could be resolved to each enantiomer by HPLC using a chiral column. The calixarenes with planar chirality recognized the chirality of guest molecules. Thus, the (-)-receptor resolved strongly forms 1:1 complex with (R)-(+)-alpha-phenylethylammonium picrate.
authors.affiliation: Department of Chemistry, Gunma University, Kiryu, Japan. okada@chem.gunma-u.ac.jp
authors.forename: Yukihiro
authors.initials: Y
authors.lastname: Okada
authors.forename: Manabu
authors.initials: M
authors.lastname: Mizutani
authors.forename: Fuyuhiko
authors.initials: F
authors.lastname: Ishii
authors.forename: Jun
authors.initials: J
authors.lastname: Nishimura