CHIRAL DITHIA[N]PARACYCLOPHANES - SYNTHESIS, CRYSTAL-STRUCTURE, AND CHIROPTICAL

The synthesis of the shortly bridged dithia[n]paracyclophanes (n=7, 8) 1-5 was achieved by the cesium-assisted high-dilution cyclization for the first time. A chiral molecular structure is induced by the patter n of the two methyl substituents. A structure with CI symmetry for the dithia[7]paracyclophane 1 is proven by X-ray structure analysis and b y low-temperature NMR experiments. The benzene ring is strongly deform ed to a boat-shaped conformation. Enantiomeric separation of the cyclo phanes 2-5 and the circular dichrograms of the enantiomers are discuss ed. Copyright (C) 1996 Elsevier Science Ltd