title: Calix[4]arene-based bis[2]catenanes: synthesis and chiral resolution.
abstract: The exclusive formation of hydrogen-bonded dimers between tetraaryl and tetratosylurea calix[4]arenes has been used to prepare a series of ten "bisloop" tetraurea calix[4]arenes 3, in which adjacent phenylurea groups are covalently linked through alpha,omega-dioxyalkane chains. This dimerization with tetratosylurea 2 as template preorganizes the alkenyl residues of tetra(m-alkenyloxyphenyl) ureas 1 and enables their selective connection in high yield (up to 95 %) by olefin metathesis followed by hydrogenation. The "bisloop" calixarenes 3 also exclusively form heterodimers with 1. Thus, in a separated metathesis/hydrogenation sequence, a series of 14 cyclic bis[2]catenanes 4, in which two calix[4]arenes are connected through their wide rims by two pairs of interlocked rings (total size 29 to 41 atoms), were prepared in yields of up to 97 %. Optical resolution of these chiral bis[2]catenanes was studied by HPLC on chiral stationary phases. The single-crystal X-ray structure of one example (4(P,10)) confirmed the interlocking rings and revealed that the hydrogen-bonded dimeric capsule of the calix[4]arene can be "completely" opened.
authors.affiliation: Fachbereich Chemie, Pharmazie und Geowissenschaften, Abteilung Lehramt Chemie, Johannes Gutenberg-Universität Mainz, Duesbergweg 10-14, 55099 Mainz, Germany.
authors.forename: Olena
authors.initials: O
authors.lastname: Molokanova
authors.forename: Anca
authors.initials: A
authors.lastname: Bogdan
authors.forename: Myroslav O
authors.initials: MO
authors.lastname: Vysotsky
authors.forename: Michael
authors.initials: M
authors.lastname: Bolte
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Ikai
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Okamoto
authors.forename: Volker
authors.initials: V
authors.lastname: Böhmer
mesh_terms: D047250:Calixarenes / Q000138:chemical synthesis / Q000737:chemistry*; D043863:Catenanes / Q000737:chemistry*; D018360:Crystallography, X-Ray; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D015394:Molecular Structure; D013237:Stereoisomerism
chemical_list: D043863:Catenanes; D047250:Calixarenes