Structure-activity relationships of sandalwood odorants: total synthesis and fragrance properties of cyclopropano-beta-santalol.

The synthesis and odor properties of cyclopropano-beta-santalol, a new santalol analogue, are described. The exocyclic double bond of the original molecule, beta-santalol, is replaced by a cyclopropane ring. Despite the analogies in the binding properties between the double bond and cyclopropane this change in the bulky hydrophobic part of the molecule leads to the complete loss of the characteristic sandalwood odor: in an olfactory evaluation the (Z)-product appears spicy and sweet, the (E)-isomer woody, but neither of them exhibits the typical sandalwood character.