Provided is a 3-acyloxymethyl-3-butenal acetal compound of General Formula (10):

##STR00001##

wherein R.sup.1 and R.sup.2, which may be the same or different, are each an alkyl group having 1 to 6 carbon atoms, or are bonded to each other to form a divalent alkylene group having 2 to 12 carbon atoms, and X.sup.1 is an acyloxy group having 1 to 6 carbon atoms.

A method for producing a 7-methyl-3-methylene-7-octenyl carboxylate compound (1), the method including the step of coupling a nucleophilic reagent of General Formula (8): ##STR00001##
wherein M is a cationic moiety, with an acetal compound of General Formula (9): ##STR00002##
wherein R.sup.1 and R.sup.2, which may be the same or different, are each an alkyl group having 1 to 6 carbon atoms, or are bonded to each other to form a divalent alkylene group having 2 to 12 carbon atoms, and X is a leaving group, to obtain the 7-methyl-3-methylene-7-octenal acetal compound.

A method for producing a 7-methyl-3-methylene-7-octenyl carboxylate compound (1), the method including the step of coupling a nucleophilic reagent of General Formula (8): ##STR00001##
wherein M is a cationic moiety, with an acetal compound of General Formula (9): ##STR00002##
wherein R.sup.1 and R.sup.2, which may be the same or different, are each an alkyl group having 1 to 6 carbon atoms, or are bonded to each other to form a divalent alkylene group having 2 to 12 carbon atoms, and X is a leaving group, to obtain the 7-methyl-3-methylene-7-octenal acetal compound.

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).

5,9-dimethyl-9-hydroxy-decen-4-al, having the formula (I) ##STR00001##

5,9-dimethyl-9-hydroxy-decen-4-al, having the formula (I) ##STR00001##

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.