The present invention relates to novel 4-(3',8',8'-trimethyl-2', 3',4',7',8',8a'-hexahydro-1H-3a',7'-methanoazulen-6'-yl)butan-2-ones of formula (I), optionally substituted with a methoxy at positions C-1 and C-3, as defined herein, and their use as amber-scented fragrance substances. In particular, the present invention relates to the use of compounds (1), (2), and (3) as fragrance substances and fixatives, as well as their incorporation into fragrance compositions in combination with other fragrance substances. Furthermore, the present invention relates to a method for perfuming a product with the compounds according to the invention and a corresponding fragranced product.