Synthesis of Methyl-5,6,11,12-tetrahydrodibenzo[a,e]cyclooctenols and a conformational study by proton nuclear magnetic resonance

Abstract

A series of methyl-5,6,11,12-tetrahydrodibenzo[a,e]cycloocten-5-ols were synthesized, and their conformations assigned by means of proton nuclear magnetic resonance. Placing substituents in three of the four available sites on the eight-membered ring enabled the chemical shifts of the geminal proton to be observed. It was found that the three sites have intrinsic chemical shifts. The compounds studied were found to populate a twist-boat conformation, with bulky substituents preferentially populating the axial site.