Collect. Czech. Chem. Commun. 1984, 49, 513-532

Isomeric oxatricyclodecanones with non-planar lactone groups: Synthesis, absolute configuration, NMR and X-ray study

Miloš Tichýa, Ahmed Faraga, Miloš Buděšínskýa, Ludmila P. Otroshchenkob, Tatjana A. Shibanovab and Karel Bláhaa

a Institute of Organic Chemistry and Biochemistry, Czechoslovak Academy of Sciences, 166 10 Prague 6, ČSSR
b Institute of Crystallography, Academy of Sciences USSR, Moscow, USSR


Several rigid polycyclic lactones, potentially suitable as models for investigation of the lactone grouping geometry, were synthesized. (3S)-4-Oxatricyclo[,7]decan-5-one ((+)-I), (3R)-5-oxatricyclo[,8]decan-4-one ((+)-III) and (4S)-5-oxatricyclo[,8]decan-6-one ((-)-VIII) were prepared by acid-catalyzed lactonization of (2R)-endo-bicyclo[2.2.2]oct-5-ene-2-carboxylic acid. (1S)-4-Oxatricyclo[,8]decan-5-one ((-)-II) was synthesized from (2S, 5S)-endo,endo-bicyclo[2.2.2]-octane-2,5-dicarbolyxic acid. The structure of VIII was unequivocally proved by its NMR, spectra and the geometry of III was determined by X-ray analysis. The absolute configuration of (+)-III was assigned by correlation with (1R)-bicyclo[3.2.1]nonan-6-one. The acid-induced interconversion of I, II, III and VIII was studied. Lactones II and III represent suitable rigid models for investigations of non-planar lactone groups of known chirality and geometry.