The invention relates to bicyclic aldehydes and ketones of formula (I): 
wherein
n is 1 or 2;
R1 and R4 are independently H or CH3; and
R2 and R3 are independently H, CH3 or CH2CH3 
The invention also provides odorant compositions containing at least one compound of formula (I). A process for the manufacture of R1-methyl substituted compounds of formula (I) having a bridgehead-positioned double bond, as well as intermediates thereof is also provided.
                            本发明涉及公式(I)的双环醛和酮:其中n为1或2;R1和R4独立地为H或
CH3;R2和R3独立地为H,   或CH2   。本发明还提供含有至少一种公式(I)化合物的
香料组合物。本发明还提供制备具有桥头位置双键的R1-甲基取代化合物的方法,以及其中间体。