Process for preparing 2-exo-(2-Methylbenzyloxy)-1-methyl-4-isopropyl-7-oxabicy-clo[2.2.1]heptane

A process for preparing (±)-2-exo-(2-Methylbenzyloxy) -1-methyl-4-isopropyl-7-oxabicyclo[2.2.1]heptane of the formula (I)

• any one of its individual enantiomers or any non-racemic mixture thereof comprising the steps of
• (a) reacting (±)-2-exo-hydroxy-1-methyl-4-isopropyl-7-oxabicyclo[2.2.1]heptane of the formula (II)
• any one of its individual enantiomers or any non-racemic mixture thereof with elemental sodium to form a sodium salt of the formula (III)
• any one of its individual enantiomers or any non-racemic mixture thereof, and
• (b) reacting the sodium salt of the formula (III), any of its individual enantiomers or any non-racemic mixture thereof with a 2-Methylbenzyl compound of the formula (IV)
• wherein X is a leaving group,
• wherein the steps (a) and (b) are conducted in the presence of at least one substantially anhydrous inert organic solvent selected from hydrocarbons,
• wherein the substantially anhydrous inert organic solvent has a water content lower than 0.1% by weight (Based on a total weight of the substantially anhydrous inert organic solvent, and
• wherein the elemental sodium used in step (a) is present in the form of dispersed sodium particles and step (b) is conducted in the presence of at least one phase transfer catalyst selected from quaternary phosphonium salts.