Optically active nine-membered rings incorporating the 8- and 8′-positions of 1,1′-binaphthyl. Part 2. Oxygen, sulphur, and selenium heterocycles. Synthesis, 1H nuclear magnetic resonance spectra, and absolute configuration

Abstract

The preparation of 8-oxa-, 8-thia-, 8-selena-, and 8-dioxothia-8,9-dihydro-7H-cyclonona[1,2,3-de:4,5,6-d′e′]dinaphthalene, racemic and optically active, is described. Enantiomeric forms were synthesised from optically active precursors of known absolute configuration, thus the absolute configurations of the new compounds are established. ¹H N.m.r. spectra are discussed.