Abstract A series of compounds possessing a 'Steroid-type'scent and related to 4-(4′-t- butylcyclohexyl)-4-methyl-2-pentanones (1 and 2) has been synthesized. The odor of these compounds has been found to be dependent on their conformation; only when the molecule can assume a steroid-like shape there is an interaction with the odor chemoreceptor.