The present invention relates to an improved way to produce 2-methyl-4-(2,6,6-trimethyl-1-cyclohexen-1-yl)-2-butenal and derivatives thereof.

A method for preparing a compound of formula (I) ##STR00001## in which R1 is selected from H and alkyls, R2 is selected from H, alkyls, OR′ where R′ is selected from alkyls, silyls, CO-alkyl, R3 is selected from the acyl groups of the CO(R″) type, and the CO(OR″), CO(NR″R′″), PO(OR″)(OR′″), PO(OR″)(R′″) groups where R″ and R′″, independently of each other, are selected from H and alkyls, R represents a C(R4)═C(R5)(R6) group where R4, R5 and R6, independently of each other, are selected from H, linear or cyclic alkyls and alkenyls, aryls, alkylaryls, or R4 and R5 together form a saturated or unsaturated, substituted or unsubstituted ring, from a compound of formula (II) ##STR00002## or a compound of formula (III) ##STR00003## in which, R, R1, R2 and R3 have the above definition.

A method for preparing a compound of formula (I) ##STR00001## in which R1 is selected from H and alkyls, R2 is selected from H, alkyls, OR′ where R′ is selected from alkyls, silyls, CO-alkyl, R3 is selected from the acyl groups of the CO(R″) type, and the CO(OR″), CO(NR″R′″), PO(OR″)(OR′″), PO(OR″)(R′″) groups where R″ and R′″, independently of each other, are selected from H and alkyls, R represents a C(R4)═C(R5)(R6) group where R4, R5 and R6, independently of each other, are selected from H, linear or cyclic alkyls and alkenyls, aryls, alkylaryls, or R4 and R5 together form a saturated or unsaturated, substituted or unsubstituted ring, from a compound of formula (II) ##STR00002## or a compound of formula (III) ##STR00003## in which, R, R1, R2 and R3 have the above definition.

The present invention provides a process for preparing a (1,2-dimethyl-3-methylenecyclopentyl)acetate compound of the following general formula (3), wherein R represents a linear or branched alkyl group having 1 to 4 carbon atoms, the process comprising subjecting a haloacetaldehyde alkyl 2,3-dimethyl-2-cyclopentenyl acetal compound of the following general formula (1), wherein R is as defined above, and Y represents a halogen atom, to a dehydrohalogenation reaction in the presence of a base, followed by a rearrangement reaction to obtain a (1,2-dimethyl-2-cyclopentenyl)acetate compound of the following general formula (2), wherein R is as defined above, and subjecting the (1,2-dimethyl-2-cyclopentenyl)acetate compound (2) to an epoxidation reaction, followed by an isomerization reaction and then a methylenation reaction to obtain the (1,2-dimethyl-3-methylenecyclopentyl)acetate compound of the following general formula (3). The present invention also provides a process for preparing (1,2-dimethyl-3-methylenecyclopentyl)acetaldehyde of the following formula (4), the process comprising the aforesaid process for preparing the (1,2-dimethyl-3-methylenecyclopentyl)acetate compound (3), and converting an alkoxycarbonylmethyl group (i.e., —CH.sub.2C(═O)OR) of the (1,2-dimethyl-3-methylenecyclopentyl)acetate compound (3) to a formylmethyl group (i.e., —CH.sub.2CHO) to obtain (1,2-dimethyl-3-methylenecyclopentyl)acetaldehyde (4). ##STR00001##

The present invention provides a process for preparing a (1,2-dimethyl-3-methylenecyclopentyl)acetate compound of the following general formula (3), wherein R represents a linear or branched alkyl group having 1 to 4 carbon atoms, the process comprising subjecting a haloacetaldehyde alkyl 2,3-dimethyl-2-cyclopentenyl acetal compound of the following general formula (1), wherein R is as defined above, and Y represents a halogen atom, to a dehydrohalogenation reaction in the presence of a base, followed by a rearrangement reaction to obtain a (1,2-dimethyl-2-cyclopentenyl)acetate compound of the following general formula (2), wherein R is as defined above, and subjecting the (1,2-dimethyl-2-cyclopentenyl)acetate compound (2) to an epoxidation reaction, followed by an isomerization reaction and then a methylenation reaction to obtain the (1,2-dimethyl-3-methylenecyclopentyl)acetate compound of the following general formula (3). The present invention also provides a process for preparing (1,2-dimethyl-3-methylenecyclopentyl)acetaldehyde of the following formula (4), the process comprising the aforesaid process for preparing the (1,2-dimethyl-3-methylenecyclopentyl)acetate compound (3), and converting an alkoxycarbonylmethyl group (i.e., —CH.sub.2C(═O)OR) of the (1,2-dimethyl-3-methylenecyclopentyl)acetate compound (3) to a formylmethyl group (i.e., —CH.sub.2CHO) to obtain (1,2-dimethyl-3-methylenecyclopentyl)acetaldehyde (4). ##STR00001##

The alpha alkylation of an aldehyde with a polycyclic olefin followed by a ring opening step is presented in order to provide a compound of formula (I) in the form of any one of its stereoisomers or a mixture thereof and where in R represents a hydrogen atom or C.sub.1-8 linear alkyl group; R.sup.1, R.sup.2, R.sup.3, and R.sup.4 represent, when taken separately, independently of each other, a hydrogen atom or a C.sub.1-2 linear alkyl group or a C.sub.3-4 linear or branched alkyl group; or R.sup.2 and R.sup.3, when taken together, represent a C.sub.4-10 linear, branched or cyclic alkanediyl group and n is 1 or 2 is presented. ##STR00001##

The alpha alkylation of an aldehyde with a polycyclic olefin followed by a ring opening step is presented in order to provide a compound of formula (I) in the form of any one of its stereoisomers or a mixture thereof and where in R represents a hydrogen atom or C.sub.1-8 linear alkyl group; R.sup.1, R.sup.2, R.sup.3, and R.sup.4 represent, when taken separately, independently of each other, a hydrogen atom or a C.sub.1-2 linear alkyl group or a C.sub.3-4 linear or branched alkyl group; or R.sup.2 and R.sup.3, when taken together, represent a C.sub.4-10 linear, branched or cyclic alkanediyl group and n is 1 or 2 is presented. ##STR00001##

The alpha alkylation of an aldehyde with a polycyclic olefin followed by a ring opening step is presented in order to provide a compound of formula (I) in the form of any one of its stereoisomers or a mixture thereof and where in R represents a hydrogen atom or C.sub.1-8 linear alkyl group; R.sup.1, R.sup.2, R.sup.3, and R.sup.4 represent, when taken separately, independently of each other, a hydrogen atom or a C.sub.1-2 linear alkyl group or a C.sub.3-4 linear or branched alkyl group; or R.sup.2 and R.sup.3, when taken together, represent a C.sub.4-10 linear, branched or cyclic alkanediyl group and n is 1 or 2 is presented. ##STR00001##

The present invention discloses a method for preparing aldehydes or ketones via aerobic oxidation of alcohols with the copper salts and nitroxide radicals as catalysts. Both oxygen and air could be used as oxidants, after 4 to 48 hours of reaction in an organic solvent at room temperature, the alcohols are efficiently oxidized to the corresponding aldehydes or ketones. The present invention has the following advantages: easy to operate, refraining from using chlorides which are corrosive to equipment, readily available raw materials and reagents, mils reaction conditions, the broad substrate scope, good functional group tolerance, convenient purification, environmentally friendly and no pollution. Thus, the method is suitable for industrial production.

The present invention discloses a method for preparing aldehydes or ketones via aerobic oxidation of alcohols with the copper salts and nitroxide radicals as catalysts. Both oxygen and air could be used as oxidants, after 4 to 48 hours of reaction in an organic solvent at room temperature, the alcohols are efficiently oxidized to the corresponding aldehydes or ketones. The present invention has the following advantages: easy to operate, refraining from using chlorides which are corrosive to equipment, readily available raw materials and reagents, mils reaction conditions, the broad substrate scope, good functional group tolerance, convenient purification, environmentally friendly and no pollution. Thus, the method is suitable for industrial production.