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Nitro‐ und Allyloxy‐substituierte helicale [2.2]Metacyclophane: Synthese, Circulardichroismus und Röntgen‐Kristallstrukturanalysen
Author(s) -
Knops Peter,
Windscheif PaulMichael,
Vögtle Fritz,
Roloff Albrecht,
Jansen Martin,
Nieger Martin,
Niecke Edgar,
Okamoto Yoshio
Publication year - 1991
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.19911240719
Subject(s) - chemistry , racemization , enantiomer , sulfone , nitro , crystal structure , stereochemistry , ether , intramolecular force , medicinal chemistry , crystallography , organic chemistry , alkyl
Nitro‐ and Allyloxy‐Substituted Helical [2.2]Metacyclophanes: Synthesis, Circular Dichroism and Crystal Structures The preparations of the title compound 3a , intraannularly nitro‐functionalized, of the extraannularly substituted reference compound 3b , and of the sulfone 4 are described. Enantiomeric resolution of these helical phanes was accomplished on (+)‐PTrMA and cellulose tris(3,5‐dimethylphenyl)carbamate by HPLC. Racemization of the enantiomers of 3b is faster than that of the previously reported extraannularly substituted phanes. The crystal structure of 3a as well as that of the allyl ether 3d show severe distortions of the benzene rings; the CD spectrum of 3a is pointing at an intramolecular charge‐transfer complex, an effect that cannot be evaluated from the CD spectrum of 3b .