An efficient process for preparing (9E,11Z)-9,11-hexadecadienal of formula (4) ##STR00001##
is provided. The process includes at least steps of: conducting a nucleophilic substitution reaction between an (8E,10Z)-8,10-pentadecadienyl magnesium halide derived from an (8E,10Z)-1-halo-8,10-pentadecadiene of (1): ##STR00002##
and an orthoformate ester (2) ##STR00003##
to thereby prepare a (9E, 11Z)-1,1-dialkoxy-9, 11-hexadecadiene (3): ##STR00004##
and hydrolyzing the (9E, 11Z)-1,1-dialkoxy-9,11-hexadecadiene (3) to obtain (9E, 11Z)-9,11-hexadecadienal (4).

The object of the present invention is to provide a process for preparing a 5-alken-1-yne compound efficiently at low costs and a process for preparing (2E,6Z)-2,6-nonadienal by making use of the aforesaid process for preparing the 5-alken-1-yne compound.

There is provided a process for preparing a 5-alken-1-yne compound of the following formula (4): Y-Z-CR.sup.1CR.sup.2(CH.sub.2).sub.2CCH (4) in which Y in formula (4) represents a hydrogen atom or a hydroxyl group, the process comprising at least steps of: subjecting (i) an alkenylmagnesium halide compound prepared from a haloalkene compound of the following formula (1): Y-Z-CR.sup.1CR.sup.2(CH.sub.2).sub.2-X.sup.1 (1) and (ii) an alkyne compound of the following formula (2): X.sup.2=CCSi(R.sup.3)(R.sup.4)(R.sup.5) (2) to a coupling reaction to form a silane compound of the following formula (3): Y-Z-CR.sup.1CR.sup.2(CH.sub.2).sub.2CCSi(R.sup.3)(R.sup.4)(R.sup.5) (3); and subjecting the silane compound (3) to a desilylation reaction to form the 5-alken-1-yne compound (4).

The object of the present invention is to provide a process for preparing a 5-alken-1-yne compound efficiently at low costs and a process for preparing (2E,6Z)-2,6-nonadienal by making use of the aforesaid process for preparing the 5-alken-1-yne compound.

There is provided a process for preparing a 5-alken-1-yne compound of the following formula (4): Y-Z-CR.sup.1CR.sup.2(CH.sub.2).sub.2CCH (4) in which Y in formula (4) represents a hydrogen atom or a hydroxyl group, the process comprising at least steps of: subjecting (i) an alkenylmagnesium halide compound prepared from a haloalkene compound of the following formula (1): Y-Z-CR.sup.1CR.sup.2(CH.sub.2).sub.2-X.sup.1 (1) and (ii) an alkyne compound of the following formula (2): X.sup.2=CCSi(R.sup.3)(R.sup.4)(R.sup.5) (2) to a coupling reaction to form a silane compound of the following formula (3): Y-Z-CR.sup.1CR.sup.2(CH.sub.2).sub.2CCSi(R.sup.3)(R.sup.4)(R.sup.5) (3); and subjecting the silane compound (3) to a desilylation reaction to form the 5-alken-1-yne compound (4).

Provided herein are convenient and efficient processes for preparing (2E,6Z)-2,6-nonadienal and (2E)-6,7-epoxy-2-nonenal with a reduced number of steps.

For instance, provided herein is a process for preparing (2E,6Z)-2,6-nonadienal, including at least steps of subjecting a (6,6-dialkoxy-4-hexenylidene)triarylphosphorane compound of the general formula: Ar.sub.3PCH(CH.sub.2).sub.2CHCHCH(OR.sup.1)(OR.sup.2) to a Witting reaction with propanal to form a 1,1-dialkoxy-(6Z)-2,6-nonadiene compound of the general formula (6); and subjecting the 1,1-dialkoxy-(6Z)-2,6-nonadiene compound to hydrolysis to form (2E,6Z)-2,6-nonadienal. Also provided is a process for preparing (2E)-cis-6,7-epoxy-2-nonenal of the formula (8), comprising a step of subjecting (2E,6Z)-2,6-nonadienal thus obtained to epoxidation to form (2E)-cis-6,7-epoxy-2-nonenal.

##STR00001##

Provided herein are convenient and efficient processes for preparing (2E,6Z)-2,6-nonadienal and (2E)-6,7-epoxy-2-nonenal with a reduced number of steps.

For instance, provided herein is a process for preparing (2E,6Z)-2,6-nonadienal, including at least steps of subjecting a (6,6-dialkoxy-4-hexenylidene)triarylphosphorane compound of the general formula: Ar.sub.3PCH(CH.sub.2).sub.2CHCHCH(OR.sup.1)(OR.sup.2) to a Witting reaction with propanal to form a 1,1-dialkoxy-(6Z)-2,6-nonadiene compound of the general formula (6); and subjecting the 1,1-dialkoxy-(6Z)-2,6-nonadiene compound to hydrolysis to form (2E,6Z)-2,6-nonadienal. Also provided is a process for preparing (2E)-cis-6,7-epoxy-2-nonenal of the formula (8), comprising a step of subjecting (2E,6Z)-2,6-nonadienal thus obtained to epoxidation to form (2E)-cis-6,7-epoxy-2-nonenal.

##STR00001##

An efficient process for preparing (9E,11Z)-9,11-hexadecadienal of formula (4)

##STR00001##

is provided. The process includes at least steps of: conducting a nucleophilic substitution reaction between an (8E,10Z)-8,10-pentadecadienyl magnesium halide derived from an (8E,10Z)-1-halo-8,10-pentadecadiene of (1):

##STR00002##

and an orthoformate ester (2)

##STR00003##

to thereby prepare a (9E, 11Z)-1,1-dialkoxy-9, 11-hexadecadiene (3):

##STR00004##

and hydrolyzing the (9E, 11Z)-1,1-dialkoxy-9,11-hexadecadiene (3) to obtain (9E, 11Z)-9,11-hexadecadienal (4).

An efficient process for preparing (9E,11Z)-9,11-hexadecadienal of formula (4)

##STR00001##

is provided. The process includes at least steps of: conducting a nucleophilic substitution reaction between an (8E,10Z)-8,10-pentadecadienyl magnesium halide derived from an (8E,10Z)-1-halo-8,10-pentadecadiene of (1):

##STR00002##

and an orthoformate ester (2)

##STR00003##

to thereby prepare a (9E, 11Z)-1,1-dialkoxy-9, 11-hexadecadiene (3):

##STR00004##

and hydrolyzing the (9E, 11Z)-1,1-dialkoxy-9,11-hexadecadiene (3) to obtain (9E, 11Z)-9,11-hexadecadienal (4).

To provide a novel method for producing a halogenated acrylic acid derivative. A compound represented by the formula (1): ##STR00001##
(wherein each of R.sup.1 and R.sup.2 which are independent of each other, is a hydrogen atom or a monovalent group essentially containing a carbon atom, or R.sup.1 and R.sup.2 together form a ring, R.sup.3 is a monovalent group capable of being desorbed by R.sup.3OH removal reaction, and each of R.sup.4 and R.sup.5 which are independent of each other, is a hydrogen atom or a monovalent group essentially containing a carbon atom) and having a boiling point of at most 500 C., is subjected to R.sup.3OH removal reaction in a vapor phase in the presence of a solid catalyst to obtain an ethene derivative represented by the formula (2): ##STR00002##
the ethene derivative represented by the formula (2) and a halogenated methane represented by the formula (3):
CHXYZ(3)
(wherein each of X, Y and Z which are independent of one another, is a halogen atom) are reacted in the presence of a basic compound and a phase transfer catalyst, to obtain a cyclopropane derivative represented by the formula (4): ##STR00003##
and the cyclopropane derivative represented by the formula (4) is reacted by heating in a liquid phase or in a vapor phase to obtain a halogenated acrylic acid ester derivative represented by the formula (5): ##STR00004##

To provide a novel method for producing a halogenated acrylic acid derivative. A compound represented by the formula (1): ##STR00001##
(wherein each of R.sup.1 and R.sup.2 which are independent of each other, is a hydrogen atom or a monovalent group essentially containing a carbon atom, or R.sup.1 and R.sup.2 together form a ring, R.sup.3 is a monovalent group capable of being desorbed by R.sup.3OH removal reaction, and each of R.sup.4 and R.sup.5 which are independent of each other, is a hydrogen atom or a monovalent group essentially containing a carbon atom) and having a boiling point of at most 500 C., is subjected to R.sup.3OH removal reaction in a vapor phase in the presence of a solid catalyst to obtain an ethene derivative represented by the formula (2): ##STR00002##
the ethene derivative represented by the formula (2) and a halogenated methane represented by the formula (3):
CHXYZ(3)
(wherein each of X, Y and Z which are independent of one another, is a halogen atom) are reacted in the presence of a basic compound and a phase transfer catalyst, to obtain a cyclopropane derivative represented by the formula (4): ##STR00003##
and the cyclopropane derivative represented by the formula (4) is reacted by heating in a liquid phase or in a vapor phase to obtain a halogenated acrylic acid ester derivative represented by the formula (5): ##STR00004##

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).