can be used much lower concentrations than these can typically be used when these compounds are directly applied for perfuming some of the consumer products mentioned above the invention also relates to a process for the preparation of the compounds of formula i according to the process of the invention an alcohol of formula is subjected to a diels alder type reaction in the presence of a methylvinyl ketone and this reaction is followed by dehydration and cyclisation these three steps are effected in a one pot u201c cascade u201d reaction the alcohol of formula ii is a novel compound and constitutes another object of the present invention the latter can be obtained by a grignard type reaction starting from epoxymyrcene the reaction conditions are described in more detail in an example presented hereafter the invention will now be described in greater detail in the following examples wherein the temperatures are indicated in degrees centigrade and the abbreviations have the usual meaning in the art a 1230 ml of a solution of ch 3 mgcl 3m in tetrahydrofurane fluka was added to 26 5 g of cubr fluka in 11 of diisopropylether with stirring at 0 u00b0 bath temperature after one night the reaction mixture was cooled to u2212 20 u00b0 and 467 g of epoxymyrcene 2 3 4 epoxy 4 methylpentyl 1 3 butadiene in 4 l of isopropylether were added dropwise after.