Flüssigkeits-Chromatographie an Triacetylcellulose 6. Helicale Phenanthrene: 1. Synthesis, Chromatographic Enrichment of Enantiomers, and Barriers to Enantiomerization of Helical Phenanthrenes

Abstract

Enantiomerization barriers (Table 1) for novel 4,5-disubstituted phenanthrenes of types A and B have been determined by coalescence of 1H NMR signals or by thermal racemization of chromatographically enriched enantiomers. The barriers depend upon the size of the groups R = CMe3, Br, Me, Cl, OBz in A and B, the behaviour of annelated benzo rings instead of R being particularly considered.