| Abstract: | 100 Mc/s proton NMR. spectra of the two diastereoisomeric thujanes obtained by reduction natural thujone have been measured and are given a detailed analysis. The relative configurations of the two hydrocarbons are deduced. Together with the known R-configuration at C(1) the absolute configurations can be derived, (?)-cis-thujane having the (1R:4S:5R)- and (+)-trans-thujane the (1R:4R:5R)-configuration. It can be shown that the trans-isomer adopts a boat-like conformation of the bicyclohexane ring system whereas cis-thujane prefers a half-chair conformation with a flattened cyclopentane ring. |
