Conformational studies of sterically comparable 2,4-disubstituted bicyclo[3.3.1]nonan-9-one systems .2.

Abstract

Condensation of cyclohexanone with cinnamaldehyde and morpholine in the presence of anhydrous CeCl3 results in the formation of two isomers of 2-morpholino-4-phenylbicyclo[3.3.1]nonan-9-one, besides two other products. The stereochemistry of the minor isomer has been determined with the help of H-1 NMR, COSY, C-13 NMR techniques and H-1 shift reagent studies on sterically comparable 2,4-diphenyl-bicyclo[3.3.1]nonan-9-one. In this case the molecule exists in a twin-chair conformation with the two substituents diequatorially oriented.