Methods of producing a 2,4-dienal acetal compound and a 2,4-dienal compound useful as synthesis intermediates of a sex pheromone compound having a conjugated diene structure or a conjugated triene structure. More specifically, a method produces a 2,4-dienal acetal compound of Formula (2): R.sup.1CHCHCHCHCH(OR.sup.2)(OR.sup.3), including a step of subjecting a 2-enal acetal compound having a leaving group X at position C5 and being expressed by Formula (1): R.sup.1CHXCH.sub.2CHCHCH(OR.sup.2)(OR.sup.3) to an elimination reaction in the presence of a base to obtain the 2,4-dienal acetal compound (2); and a method for producing a 2,4-dienal compound of Formula (3): R.sup.1CHCHCHCHCHO, further including a step of deprotecting the 2,4-dienal acetal compound (2) to obtain the 2,4-dienal compound (3).

Provided are a 1-halo-6,9-pentadecadiene useful as an intermediate having a skipped diene skeleton and a method for producing (7Z,10Z)-7,10-hexadecadienal. More specifically, provided are a method for producing (7Z,10Z)-7,10-hexadecadienal including steps of subjecting a Grignard reagent formed from a (6Z,9Z)-1-halo-6,9-pentadecadiene to a nucleophilic substitution reaction with an orthoformate ester to obtain a (7Z,10Z)-1,1-dialkoxy-7,10-hexadecadiene; and hydrolyzing the (7Z,10Z)-1,1-dialkoxy-7,10-hexadecadiene in the absence of an oxidation reaction to obtain the (7Z,10Z)-7,10-hexadecadienal; and the like.

Provided are a 1-halo-6,9-pentadecadiene useful as an intermediate having a skipped diene skeleton and a method for producing (7Z,10Z)-7,10-hexadecadienal. More specifically, provided are a method for producing (7Z,10Z)-7,10-hexadecadienal including steps of subjecting a Grignard reagent formed from a (6Z,9Z)-1-halo-6,9-pentadecadiene to a nucleophilic substitution reaction with an orthoformate ester to obtain a (7Z,10Z)-1,1-dialkoxy-7,10-hexadecadiene; and hydrolyzing the (7Z,10Z)-1,1-dialkoxy-7,10-hexadecadiene in the absence of an oxidation reaction to obtain the (7Z,10Z)-7,10-hexadecadienal; and the like.

Methods of producing a 2,4-dienal acetal compound and a 2,4-dienal compound useful as synthesis intermediates of a sex pheromone compound having a conjugated diene structure or a conjugated triene structure. More specifically, a method produces a 2,4-dienal acetal compound of Formula (2): R.sup.1CHCHCHCHCH(OR.sup.2)(OR.sup.3), including a step of subjecting a 2-enal acetal compound having a leaving group X at position C5 and being expressed by Formula (1): R.sup.1CHXCH.sub.2CHCHCH(OR.sup.2)(OR.sup.3) to an elimination reaction in the presence of a base to obtain the 2,4-dienal acetal compound (2); and a method for producing a 2,4-dienal compound of Formula (3): R.sup.1CHCHCHCHCHO, further including a step of deprotecting the 2,4-dienal acetal compound (2) to obtain the 2,4-dienal compound (3).

Methods of producing a 2,4-dienal acetal compound and a 2,4-dienal compound useful as synthesis intermediates of a sex pheromone compound having a conjugated diene structure or a conjugated triene structure. More specifically, a method produces a 2,4-dienal acetal compound of Formula (2): R.sup.1CHCHCHCHCH(OR.sup.2)(OR.sup.3), including a step of subjecting a 2-enal acetal compound having a leaving group X at position C5 and being expressed by Formula (1): R.sup.1CHXCH.sub.2CHCHCH(OR.sup.2)(OR.sup.3) to an elimination reaction in the presence of a base to obtain the 2,4-dienal acetal compound (2); and a method for producing a 2,4-dienal compound of Formula (3): R.sup.1CHCHCHCHCHO, further including a step of deprotecting the 2,4-dienal acetal compound (2) to obtain the 2,4-dienal compound (3).

Provided are a 1-halo-6,9-pentadecadiene useful as an intermediate having a skipped diene skeleton and a method for producing (7Z,10Z)-7,10-hexadecadienal. More specifically, provided are a method for producing (7Z,10Z)-7,10-hexadecadienal including steps of subjecting a Grignard reagent formed from a (6Z,9Z)-1-halo-6,9-pentadecadiene to a nucleophilic substitution reaction with an orthoformate ester to obtain a (7Z,10Z)-1,1-dialkoxy-7,10-hexadecadiene; and hydrolyzing the (7Z,10Z)-1,1-dialkoxy-7,10-hexadecadiene in the absence of an oxidation reaction to obtain the (7Z,10Z)-7,10-hexadecadienal; and the like.

Provided are a 1-halo-6,9-pentadecadiene useful as an intermediate having a skipped diene skeleton and a method for producing (7Z,10Z)-7,10-hexadecadienal. More specifically, provided are a method for producing (7Z,10Z)-7,10-hexadecadienal including steps of subjecting a Grignard reagent formed from a (6Z,9Z)-1-halo-6,9-pentadecadiene to a nucleophilic substitution reaction with an orthoformate ester to obtain a (7Z,10Z)-1,1-dialkoxy-7,10-hexadecadiene; and hydrolyzing the (7Z,10Z)-1,1-dialkoxy-7,10-hexadecadiene in the absence of an oxidation reaction to obtain the (7Z,10Z)-7,10-hexadecadienal; and the like.

Provided are a method for producing a terminal conjugated dienal compound without an oxidation reaction and a terminal hydroxyacetal compound useful as an intermediate in the method. More specifically, provided are a method for producing an (E)-dienal compound comprising the steps of: a metalation reaction of an alkynal acetal compound (1) to obtain an organic metal compound (2), an addition reaction of (2) to ethylene oxide to obtain a hydroxyalkynal acetal compound (3), a reduction reaction of (3) to obtain an (E)-hydroxyalkenal acetal compound (4), a functional group conversion reaction of (4) to obtain an (E)-alkenal acetal compound (5) having a leaving group X, an elimination reaction of (5) to obtain an (E)-dienal acetal compound (6), and a hydrolysis reaction of (6) to obtain the (E)-dienal compound (7); and others. ##STR00001##

Provided are a method for producing a terminal conjugated dienal compound without an oxidation reaction and a terminal hydroxyacetal compound useful as an intermediate in the method. More specifically, provided are a method for producing an (E)-dienal compound comprising the steps of: a metalation reaction of an alkynal acetal compound (1) to obtain an organic metal compound (2), an addition reaction of (2) to ethylene oxide to obtain a hydroxyalkynal acetal compound (3), a reduction reaction of (3) to obtain an (E)-hydroxyalkenal acetal compound (4), a functional group conversion reaction of (4) to obtain an (E)-alkenal acetal compound (5) having a leaving group X, an elimination reaction of (5) to obtain an (E)-dienal acetal compound (6), and a hydrolysis reaction of (6) to obtain the (E)-dienal compound (7); and others. ##STR00001##

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##