138488-65-0Relevant academic research and scientific papers
Syntheses, Enrichment of Enantiomers, and Barriers to Racemization of Twisted 9,10-Phenanthrenquinones
Fritsch, Rainer,Hartmann, Erwin,Andert, Doris,Mannschreck, Albrecht
, p. 849 - 856 (2007/10/02)
The known syntheses of the 9,10-phenanthrenequinones 10a-c were improved by the chlorotrimethylsilane modification of the acyloin condensation of biaryl diesters.The novel quinones 4a, 4b, and 12 were prepared.For the first time, enantiomers (M and P) of this class of compounds were enriched semipreparatively by liquid chromatography on optically active sorbents.The barriers to thermal racemization amount to 90-130 kJ mol-1 (Table 2) and are thus higher than the barriers for the corresponding phenanthrene hydrocarbons by roughly 20 kJ mol -1.The reasons for this increase are discussed in terms of repulsive interactions in the trans ition state of helix inversion.
TWISTED 9,10-PHENANTHRENEQUINONES: CHROMATOGRAPHIC ENRICHMENT OF ENANTIOMERS AND BARRIERS TO RACEMIZATION
Mannschreck, Albrecht,Hartmann, Erwin,Buchner, Hans,Andert, Doris
, p. 3479 - 3482 (2007/10/02)
The enantiomers (M) and (P) of helical 9,10-phenanthrenequinones were enriched by liquid chromatography with enantiomeric purities of 0.31 to 0,95.Their barriers to racemization (Table 2) were compared with the ones of the corresponding hydrocarbons.
