Process for preparing perfuming intermediates

A compound of formula (VIII):

• in the form of any one of its stereoisomers or a mixture thereof, and wherein X is a group of formula b) or d)
• in the form of any one of its stereoisomers, and
• wherein p is 0 when the dotted line is a carbon-carbon double bond and p is 1 when the dotted line is a carbon-carbon single bond;
• each R1, R2, R3, R4, R5, R6 and R7, independently from each other, represent a hydrogen atom, a C1-6 alkyl group or a C2-6 alkenyl group, each optionally substituted by a hydroxy or C1-3 alkoxy group;
• or two groups among R1, R2, R3, R4, R5, R6 and R7 are taken together and form C3-8 cycloalkyl or C5-8 cycloalkenyl group, each optionally substituted by a hydroxy, C1-3 alkyl or C1-3 alkoxy group, and the others groups have the same meaning as defined above;
• each R8, R9 and R10, independently from each other, represent a hydrogen atom, a C1-6 alkyl group or a C2-6 alkenyl group, each optionally substituted by a hydroxy or C1-3 alkoxy group;
• or two groups among R8, R9 and R10 are taken together and form C3-8 cycloalkyl or C5-8 cycloalkenyl group, each optionally substituted by a hydroxy, C1-3 alkyl or C1-3 alkoxy group, and the other group has the same meaning as defined above;
• n is 0 or 1;
• Y is a —CH═CR11—, —CHR12—CHR11— or —CH2—C(OH)R11— group wherein R11 is a hydrogen atom or a methyl or ethyl group and R12 is a hydroxy or a acetate group;
• Z is, when X is of formula d), a CHO group, a CH2OH group or a CH(ORa)(ORb)m group wherein m is 0 or 1, Ra is a C1-4 alkyl group, a trimethyl silyl group, a C(═O)—Rc group, a C(═O)—ORc group, a CH2(ORc) group, a CH(ORc)CH3 group wherein Rc is a C1-4 alkyl group;
• Rb is a C1-4 alkyl group, a C(═O)—Rc group wherein Rc is a C1-4 alkyl group;
• or Ra and Rb are taken together and represent a C2-6 alkanediyl group;
• or
• Z is, when X is of formula b), a CH(ORa)(ORb) group wherein Ra and Rb, independently from each other, are a methyl group or a C3-4 alkyl group, a C(═O)—Rc group wherein Rc is a C1-4 alkyl group;
• or Ra and Rb are taken together and represent a C3-6 alkanediyl group;
• and
• provided that when X is a group of formula (d), then at least one group among R1, R2, R3, R4, R5, R6 and R7 is a C1-6 alkyl group or a C2-6 alkenyl group, each optionally substituted by a hydroxy or C1-3 alkoxy group;
• provided that when X is a group of formula (d) and six groups among R1, R2, R3, R4, R5, R6 and R7 are a hydrogen atom, then the group among R1, R2, R3, R4, R5, R6 and R7 being not a hydrogen atom is not a methyl group;
• provided that when X is a group of formula (d) and R2, R3, R4, R5, R6 and R7 are a hydrogen atom then R1 is not a prop-1-en-2-yl group;
• and provided that 3-(4-(tert-butyl)cyclohex-1-en-1-yl)acrylaldehyde, 3-(4-(tert-butyl)-1-hydroxycyclohexyl)acrylaldehyde, 1-(tert-butyl)-4-(3,3-diethoxyprop-1-en-1-yl)benzene, 2-(4-(tert-butyl)styryl)-1,3-dioxolane, 3-(4-(tert-butyl)-1-hydroxycyclohexyl)allyl acetate, 3-(2-allyl-1-hydroxycyclohexyl)allyl acetate, 4-(tert-butyl)-1-(3-hydroxyprop-1-en-1-yl)cyclohexan-1-ol, 2-allyl-1-(3-hydroxyprop-1-en-1-yl)cyclohexan-1-ol, 2-(4-isopropylstyryl)-1,3-dioxane, 2-(4-isopropylstyryl)-4-methyl-1,3-dioxolane, 3-(2-(buta-1,3-dien-1-yl)-1-hydroxycyclohexyl)acrylaldehyde, 3-(5,5-dimethylcyclohex-1-en-1-yl)acrylaldehyde, 3-((1S,5R)-6,6-dimethylbicyclo[3.1.1]hept-2-en-3-yl)acrylaldehyde, (1R,2S,5R)-1-(3-(tert-butoxy)prop-1-en-1-yl)-2-isopropyl-5-methylcyclohexan-1-ol, 2-allyl-1-(3-hydroxyprop-1-en-1-yl)cyclohexan-1-ol, (3,3-dimethoxyprop-1-en-1-yl)benzene, are excluded.