Asymmetric catalysis in fragrance chemistry: a new synthetic approach to enantiopure Phenoxanol®, Citralis® and Citralis Nitrile®

Abstract A new approach to the synthesis of the single stereomers of the fragrances Phenoxanol ® , Citralis ® and Citralis Nitrile ® is reported. The key step of the synthesis is the asymmetric hydrogenation of ( Z )- or ( E )-3-methyl-5-phenyl-pent-2-en-1-ol, which leads to the single enantiomers of Phenoxanol ® from which both enantiomers of Citralis ® are obtained by oxidation. Treatment of these compounds with hydroxylamine finally led to Citralis Nitrile ® without any loss of enantiopurity. The odour profiles of the single enantiomers of these fragrances are reported as well.