First Optically Active Heptalenes and their Absolute Configuration

✍ Scribed by Werner Bernhard; Paul Brügger; John J. Daly; Peter Schönholzer; Roland H. Weber; Hans-Jürgen Hansen

• Publisher: John Wiley and Sons
• Year: 1985
• Tongue: German
• Weight: 1001 KB
• Volume: 68
• Category: Article
• ISSN: 0018-019X
• DOI: 10.1002/hlca.19850680215

✦ Synopsis

Abstract

It is shown that dimethyl 7‐isopropyl‐5, 10‐dimethylheptalene‐1, 2‐dicarboxylate (1) and dimethyl 5, 6, 8, 10‐tetramethylheptalene‐1, 2‐dicarboxylate (2) can be resolved via the corresponding mono‐acids and with the aid of optically active primary or secondary amines such as 1‐phenylethylamine or ephedrine into the (−)‐(P)‐ and (+)‐(M)‐enantiomeres, respectively. Characteristic for the (P)‐chirality of the heptalene π‐skeleton with C~2~ or pseudo‐C~2~ symmetry are two (−)‐CE's at the long wavelength region (450–300 nm) followed by at least one intense (+)‐CE at wavelengths about or below 300 nm. The absolute configuration of the heptalenes was correlated with the well‐established absolute configuration of (+)‐(R)‐ and (−)‐(S)‐1‐phenylethanol.