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Chirale dreilagige und kondensierte [2.2]Cyclophane Synthese, Struktur, Chiroptik
Author(s) -
Vögtle Fritz,
Ostrowicki Andreas,
Begemann Birgit,
Jansen Martin,
Nieger Martin,
Niecke Edgar
Publication year - 1990
Publication title -
chemische berichte
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 0009-2940
DOI - 10.1002/cber.19901230129
Subject(s) - chemistry , cyclophane , enantiomer , stereochemistry , selectivity , crystal structure , crystallography , organic chemistry , catalysis
Chiral Triple‐Layered and Condensed [2.2]Cyclophanes ‐ Synthesis, Structure, Chiroptical Properties The helical title compounds 1‐5 are obtained using a simple one‐step cyclisation reaction with yields reaching or increasing those obtained by application of organometallic methods in [2.2]phane syntheses. The formation of the triple‐layered phanes 1 leads with high selectivity only to the “up‐down” isomers with fixed conformation, as shown by X‐ray crystallography and by the detection of strong NOEs of the inner hydrogen atoms. For studies on structure‐chiroptic relation‐ships a systematic sequence of helical [2.2]phanes with larger arene systems is synthesized. Enrichment of enantiomers is achieved by HPLC on (+)‐PTrMA; the kinetics of racemisation and the CD spectra are discussed.