115074-94-7Relevant academic research and scientific papers
Helical and Planar-chiral Pyridinophanes - A New Synthesis and Structure/Chiroptic Relationships
Przybilla, Klaus Juergen,Voegtle, Fritz
, p. 347 - 356 (2007/10/02)
A new two-step synthesis for the strained helical oxaphanes 1-5 and for a systematic series of novel structural isomeric (2,4)-pyridinophanes (6-10) is presented.The energy barriers for ring inversion of some intermediate phanes and the kinetics of racemization of the phanes are determined.Separation and enrichment of enantiomers is achieved by HPLC on cellulose tris(3,5-dimethylphenyl)carbamate and poly(triphenylmethyl-methacrylate), resp.The circular dichroism curves of the isomers are compared with those of the corresponding protonated pyridinium compounds.The influence of the chromophor orientation on the circular dichroism is discussed. - Keywords: Circular dichroism/ Helical molecules/ Metacyclophanes/ Oxametacyclophane/ Pyridinophanes
Thia- and Oxa-metacyclophanes: Synthesis, Helicity, and Stereoselective Formation of Sulphoxides
Voegtle, Fritz,Struck, Johannes,Puff, Heinrich,Woller, Petra,Reuter, Hans
, p. 1248 - 1250 (2007/10/02)
The helical structures of the new highly strained -metacyclophanes (5) (the structure of which has been determined by X-ray crystallography) and (8) have been studied and the four stereoisomeric sulphoxides (6) obtained from (5) have been separated by h.p.l.c.; the diastereomeric excess in the oxidation of the helical sulphide (5) to yield the sulphoxides (6) is 91 percent.
