Variation of the Backbone Conjugation in NLO Model Compounds: Torsion-Angle-Restricted, Biphenyl-Based Push-Pull-Systems
作者:Jürgen Rotzler、David Vonlanthen、Alberto Barsella、Alex Boeglin、Alain Fort、Marcel Mayor
DOI:10.1002/ejoc.200901358
日期:2010.2
responses. A general synthetic route that can be implemented to access these model compounds is reported, starting from dibromo or ditriflate biphenyls. Hartwig-Buchwald cross-coupling, a selective azacycloalkylation of diaminobiphenyls and a mild oxidation of primary amines to nitro groups in the presence of a tertiary amine summarizes the synthetic pathway towards the desired model compounds. NLO properties
Synthesis of Rotationally Restricted and Modular Biphenyl Building Blocks
作者:David Vonlanthen、Jürgen Rotzler、Markus Neuburger、Marcel Mayor
DOI:10.1002/ejoc.200900805
日期:2010.1
bridges. The key intermediates 14 and 15 were transformed into the corresponding cycloheptadienones 16 and 17, which were reduced to the desired propyl-bridged biphenyls 3b and 3c. The butyl-bridged derivatives 4b and 4c were obtained from 14 and 15 by an allylation reaction followed by ring-closing metathesis (RCM) and hydrogenation. The pentyl chain in precursor 24 was obtained by two aldol C-C bond-forming
Racemisation dynamics of torsion angle restricted biphenyl push-pull cyclophanes
作者:Jürgen Rotzler、Heiko Gsellinger、Markus Neuburger、David Vonlanthen、Daniel Häussinger、Marcel Mayor
DOI:10.1039/c0ob00650e
日期:——
The thermodynamics of the atropisomerisation of torsionangle restricted, axial chiral biphenyl-based push-pull cyclophanes were studied. Using 1H NMR coalescence measurements the rotation barrier around the central C–C bond was determined to be 50 kJ mol−1 for the propyl-bridged biphenyl derivative 1b, displaying only a negligible solvent dependence. By protonation of the piperidinyl nitrogen as electron