A process of manufacturing (6R,10R)-6,10,14-trimethylpentadecan-2-one in a multistep synthesis from 6,10-dimethylundec-5-en-2-one or 6,10-dimethylundeca-5,9-dien-2-one comprising the steps a) providing a mixture of -6,10-dimethylundec-5-en-2-one and -6,10-dimethylundec-5-en-2-one or a mixture of -6,10-dimethylundeca-5,9-dien-2-one and -6,10-dimethylundeca-5,9-dien-2-one; b) separating one isomer of 6,10-dimethylundec-5-en-2-one or of 6,10-dimethylundeca-5,9-dien-2-one from the mixture of step a) c) asymmetric hydrogenation of either 6,10-dimethylundec-5-en-2-one or 6,10-dimethylundeca-5,9-dien-2-one, or a ketal of 6,10-dimethylundec-5-en-2-one or a ketal of 6,10-dimethylundeca-5,9-dien-2-one using molecular hydrogen in the presence of a chiral iridium complex and yielding -6,10-dimethylundecan-2-one; d) chemically transforming -6,10-dimethylundecan-2-one to a mixture of (R,E)-6,10,14-trimethylpentadec-5-en-2-one and (R,Z)-6,10,14-trimethylpentadec-5-en-2-one; e) separating one isomer of -6,10,14-trimethylpentadec-5-en-2-one from the mixture obtained in step d) f) asymmetric hydrogenation using molecular hydrogen in the presence of a chiral iridium complex and yielding (6R,10R)-6,10,14-trimethylpentadecan-2-one; wherein the steps a)-f) are in the order a,b,c,d,e,f; with the proviso that if in the step c) the ketal is hydrogenated before the step c) a step c o) takes place c o) forming of a ketal of the isomer of 6,10-dimethylundec-5-en-2-one or of 6,10-dimethylundeca-5,9-dien-2-one separated in step b) and that in step c) the ketal of 6,10-dimethylundec-5-en-2-one or of 6,10-dimethylundeca-5,9-dien-2-one is asymmetrically hydrogenated and after the asymmetric hydrogenation the hydrogenated ketal is hydrolysed to the ketone and yielding -6,10-dimethylundecan-2-one. a) providing a mixture of -6,10-dimethylundec-5-en-2-one and -6,10-dimethylundec-5-en-2-one or a mixture of -6,10-dimethylundeca-5,9-dien-2-one and -6,10-dimethylundeca-5,9-dien-2-one; b) separating one isomer of 6,10-dimethylundec-5-en-2-one or of 6,10-dimethylundeca-5,9-dien-2-one from the mixture of step a) c) asymmetric hydrogenation of either 6,10-dimethylundec-5-en-2-one or 6,10-dimethylundeca-5,9-dien-2-one, or a ketal of 6,10-dimethylundec-5-en-2-one or a ketal of 6,10-dimethylundeca-5,9-dien-2-one using molecular hydrogen in the presence of a chiral iridium complex and yielding -6,10-dimethylundecan-2-one; d) chemically transforming -6,10-dimethylundecan-2-one to a mixture of (R,E)-6,10,14-trimethylpentadec-5-en-2-one and (R,Z)-6,10,14-trimethylpentadec-5-en-2-one; e) separating one isomer of -6,10,14-trimethylpentadec-5-en-2-one from the mixture obtained in step d) f) asymmetric hydrogenation using molecular hydrogen in the presence of a chiral iridium complex and yielding (6R,10R)-6,10,14-trimethylpentadecan-2-one; before the step c) a step c o) takes place c o) forming of a ketal of the isomer of 6,10-dimethylundec-5-en-2-one or of 6,10-dimethylundeca-5,9-dien-2-one separated in step b) and that in step c) the ketal of 6,10-dimethylundec-5-en-2-one or of 6,10-dimethylundeca-5,9-dien-2-one is asymmetrically hydrogenated and after the asymmetric hydrogenation the hydrogenated ketal is hydrolysed to the ketone and yielding -6,10-dimethylundecan-2-one.