The alpha alkylation of an aldehyde with a polycyclic olefin followed by a ring opening step is presented in order to provide a compound of formula (I) in the form of any one of its stereoisomers or a mixture thereof and where in R represents a hydrogen atom or C.sub.1-8 linear alkyl group; R.sup.1, R.sup.2, R.sup.3, and R.sup.4 represent, when taken separately, independently of each other, a hydrogen atom or a C.sub.1-2 linear alkyl group or a C.sub.3-4 linear or branched alkyl group; or R.sup.2 and R.sup.3, when taken together, represent a C.sub.4-10 linear, branched or cyclic alkanediyl group and n is 1 or 2 is presented.

##STR00001##

The alpha alkylation of an aldehyde with a polycyclic olefin followed by a ring opening step is presented in order to provide a compound of formula (I) in the form of any one of its stereoisomers or a mixture thereof and where in R represents a hydrogen atom or C.sub.1-8 linear alkyl group; R.sup.1, R.sup.2, R.sup.3, and R.sup.4 represent, when taken separately, independently of each other, a hydrogen atom or a C.sub.1-2 linear alkyl group or a C.sub.3-4 linear or branched alkyl group; or R.sup.2 and R.sup.3, when taken together, represent a C.sub.4-10 linear, branched or cyclic alkanediyl group and n is 1 or 2 is presented.

##STR00001##

The present invention relates to novel compounds and their use as fragrance materials.

The present invention relates to novel compounds and their use as fragrance materials.

The present invention concerns a process for the preparation of an oxidized terpenes fraction which proved to be particularly useful in the preparation of sandalwood oil building blocks.

The present invention concerns a process for the preparation of an oxidized terpenes fraction which proved to be particularly useful in the preparation of sandalwood oil building blocks.