The present invention provides a process for preparing an 11-halo-3-undecene compound (7) in which X.sup.1 represents a halogen atom, the process comprising a step of subjecting a nucleophilic reagent, 3-hexenyl compound (5): in which M.sup.2 represents Li or MgZ.sup.2, wherein Z.sup.2 represents a halogen atom or a 3-hexenyl group, to a coupling reaction with a 1-halo-5-halopentane compound (6) in which X.sup.3 and X.sup.4 may be same with or different from each other and represent a halogen atom, to produce the 11-halo-3-undecene compound (7). The present invention also provides a process for preparing a 9-dodecenal compound (4): the process comprising a step of subjecting a nucleophilic reagent, 8-undecenyl compound (1) in which M.sup.1 represents Li or MgZ.sup.1, wherein Z.sup.1 represents a halogen atom or an 8-undecenyl group, and an orthoformic ester compound (2) in which R may be same with or different from each other and represents an alkyl group having 1 to 6 carbon atoms, to a nucleophilic substitution reaction to produce a 1,1-dialkoxy-9-dodecene compound (3) in which R are as defined above; and hydrolyzing the 1,1-dialkoxy-9-dodecene compound (3) thus obtained to produce the 9-dodecenal compound (4). ##STR00001##

The present invention relates to a method for the production of 2-substituted 4-hydroxy-4-methyltetrahydropyrans from the acid-catalyzed reaction of 3-methylbut-3-ene-1-ol with an aldehyde, a stable odoriferous quality being achieved and avoiding off-odors that interfere with the odor sensation.

The present invention relates to a method for the production of 2-substituted 4-hydroxy-4-methyltetrahydropyrans from the acid-catalyzed reaction of 3-methylbut-3-ene-1-ol with an aldehyde, a stable odoriferous quality being achieved and avoiding off-odors that interfere with the odor sensation.

Process for preparing an acetal from an olefin using PtI.sub.2 or PtBr.sub.2.

Process for preparing an acetal from an olefin using PtI.sub.2 or PtBr.sub.2.

Process for preparing an acetal from an olefin using an iodine-alkyl compound.

Process for preparing an acetal from an olefin using an iodine-alkyl compound.

Provided are a terminal conjugated trienal acetal compound useful as an intermediate for producing a terminal conjugated trienal compound, and a method for producing a terminal conjugated trienal compound through deprotection of the terminal conjugated trienal acetal compound. More specifically, provided are a terminal conjugated trienal acetal compound represented by General Formula (1); a method for producing a (Z,E)-terminal conjugated trienal acetal compound, the method comprising the step of: reacting a phosphonium salt represented by General Formula (7) with (E)-2,4-pentadienal through Wittig reaction to obtain a (Z,E)-terminal conjugated trienal acetal compound represented by General Formula (3); and a method for producing a terminal conjugated trienal compound, the method comprising the step of: deprotecting the terminal conjugated trienal acetal compound represented by General Formula (1) to obtain a terminal conjugated trienal compound represented by General Formula (2). ##STR00001##

Provided are a terminal conjugated trienal acetal compound useful as an intermediate for producing a terminal conjugated trienal compound, and a method for producing a terminal conjugated trienal compound through deprotection of the terminal conjugated trienal acetal compound. More specifically, provided are a terminal conjugated trienal acetal compound represented by General Formula (1); a method for producing a (Z,E)-terminal conjugated trienal acetal compound, the method comprising the step of: reacting a phosphonium salt represented by General Formula (7) with (E)-2,4-pentadienal through Wittig reaction to obtain a (Z,E)-terminal conjugated trienal acetal compound represented by General Formula (3); and a method for producing a terminal conjugated trienal compound, the method comprising the step of: deprotecting the terminal conjugated trienal acetal compound represented by General Formula (1) to obtain a terminal conjugated trienal compound represented by General Formula (2). ##STR00001##

Provided are a terminal conjugated trienal acetal compound useful as an intermediate for producing a terminal conjugated trienal compound, and a method for producing a terminal conjugated trienal compound through deprotection of the terminal conjugated trienal acetal compound. More specifically, provided are a terminal conjugated trienal acetal compound represented by General Formula (1); a method for producing a (Z,E)-terminal conjugated trienal acetal compound, the method comprising the step of: reacting a phosphonium salt represented by General Formula (7) with (E)-2,4-pentadienal through Wittig reaction to obtain a (Z,E)-terminal conjugated trienal acetal compound represented by General Formula (3); and a method for producing a terminal conjugated trienal compound, the method comprising the step of: deprotecting the terminal conjugated trienal acetal compound represented by General Formula (1) to obtain a terminal conjugated trienal compound represented by General Formula (2). ##STR00001##