The present invention relates to an acetal compound of the following general formula (1) and an acetal compound of the following general formula (2). The present invention relates to processes for preparing the acetal compound (2), comprising subjecting the acetal compound (1) to a hydrogenation reaction to form the acetal compound (2). The present invention provides a process for preparing 2,3,4,4-tetramethylcyclopentanecarbaldehyde of the following formula (3), comprising subjecting the acetal compound (2) to a hydrolysis reaction to form 2,3,4,4-tetramethylcyclopentanecarbaldehyde (3).

##STR00001##

The present invention relates to an acetal compound of the following general formula (1) and an acetal compound of the following general formula (2). The present invention relates to processes for preparing the acetal compound (2), comprising subjecting the acetal compound (1) to a hydrogenation reaction to form the acetal compound (2). The present invention provides a process for preparing 2,3,4,4-tetramethylcyclopentanecarbaldehyde of the following formula (3), comprising subjecting the acetal compound (2) to a hydrolysis reaction to form 2,3,4,4-tetramethylcyclopentanecarbaldehyde (3).

##STR00001##

The present invention relates to an acetal compound of the following general formula (1) and an acetal compound of the following general formula (2). The present invention relates to processes for preparing the acetal compound (2), comprising subjecting the acetal compound (1) to a hydrogenation reaction to form the acetal compound (2). The present invention provides a process for preparing 2,3,4,4-tetramethylcyclopentanecarbaldehyde of the following formula (3), comprising subjecting the acetal compound (2) to a hydrolysis reaction to form 2,3,4,4-tetramethylcyclopentanecarbaldehyde (3). ##STR00001##

The present invention relates to an acetal compound of the following general formula (1) and an acetal compound of the following general formula (2). The present invention relates to processes for preparing the acetal compound (2), comprising subjecting the acetal compound (1) to a hydrogenation reaction to form the acetal compound (2). The present invention provides a process for preparing 2,3,4,4-tetramethylcyclopentanecarbaldehyde of the following formula (3), comprising subjecting the acetal compound (2) to a hydrolysis reaction to form 2,3,4,4-tetramethylcyclopentanecarbaldehyde (3). ##STR00001##

A process can be used for preparing methyl methacrylate (MMA), by direct oxidative esterification of methacrolein. The MMA and polymers produced therefrom feature a very low yellowness index. A workup of the reactor output from the oxidative esterification of methacrolein allows for particularly discolouring by-products to be removed or degraded without significant MMA losses.

A process can be used for preparing methyl methacrylate (MMA), by direct oxidative esterification of methacrolein. The MMA and polymers produced therefrom feature a very low yellowness index. A workup of the reactor output from the oxidative esterification of methacrolein allows for particularly discolouring by-products to be removed or degraded without significant MMA losses.

Provided is a method with which an α-allylated cycloalkanone is obtained from a macroyclic compound used as a starting material. The method is a method for producing an α-allylated cycloalkanone represented by General Formula (IV), and the method includes a step of reacting a compound represented by General Formula (I) and/or a compound represented by General Formula (II) with a compound represented by General Formula (III) in the presence of an acid catalyst to produce an α-allylated cycloalkanone represented by General Formula (IV), the acid catalyst including an acid catalyst that includes an ammonium cation and an anion. ##STR00001##
where R.sup.1, R.sup.2, and R.sup.3 are the same or different and each of them is an alky group having 1 or mom and 4 or less of carbon atoms, the group -A.sup.1- (it should be noted that the front bond refers to a bond that binds to the carbon atom C.sup.1 and the back bond refers to a bond that binds to the carbon atom C.sup.2) is an alkylene group having 4 or more and 20 or les of carbon atoms that optionally contains a hetero atom and optionally has a substituent, and R.sup.4 is a hydrogen atom or an alkyl group having 1 or more and 4 or less of carbon atoms.

Provided is a method with which an α-allylated cycloalkanone is obtained from a macroyclic compound used as a starting material. The method is a method for producing an α-allylated cycloalkanone represented by General Formula (IV), and the method includes a step of reacting a compound represented by General Formula (I) and/or a compound represented by General Formula (II) with a compound represented by General Formula (III) in the presence of an acid catalyst to produce an α-allylated cycloalkanone represented by General Formula (IV), the acid catalyst including an acid catalyst that includes an ammonium cation and an anion. ##STR00001##
where R.sup.1, R.sup.2, and R.sup.3 are the same or different and each of them is an alky group having 1 or mom and 4 or less of carbon atoms, the group -A.sup.1- (it should be noted that the front bond refers to a bond that binds to the carbon atom C.sup.1 and the back bond refers to a bond that binds to the carbon atom C.sup.2) is an alkylene group having 4 or more and 20 or les of carbon atoms that optionally contains a hetero atom and optionally has a substituent, and R.sup.4 is a hydrogen atom or an alkyl group having 1 or more and 4 or less of carbon atoms.

Provided are a method for efficiently producing an asymmetric conjugated diyne from an inexpensive and safe alternative compound to hydroxylamine hydrochloride and a method for producing a Z,Z-conjugated diene compound from the asymmetric conjugated diyne compound thus obtained. More specifically, provided is a method for producing an asymmetric conjugated diyne compound comprising a step of subjecting a terminal alkyne compound (1): HC≡C—Z.sup.1—Y.sup.1 to a coupling reaction with an alkynyl halide (2): Y.sup.2—Z.sup.2—C≡C—X by using sodium borohydride in water and an organic solvent in the presence of a copper catalyst and a base to obtain the asymmetric conjugated diyne compound (3): Y.sup.2—Z.sup.2—C≡C—C≡C—Z.sup.1—Y.sup.1. In addition, provided is a method for producing a Z,Z-conjugated diene compound by reducing the resulting asymmetric conjugated diyne compound, or the like.

Provided are a method for efficiently producing an asymmetric conjugated diyne from an inexpensive and safe alternative compound to hydroxylamine hydrochloride and a method for producing a Z,Z-conjugated diene compound from the asymmetric conjugated diyne compound thus obtained. More specifically, provided is a method for producing an asymmetric conjugated diyne compound comprising a step of subjecting a terminal alkyne compound (1): HC≡C—Z.sup.1—Y.sup.1 to a coupling reaction with an alkynyl halide (2): Y.sup.2—Z.sup.2—C≡C—X by using sodium borohydride in water and an organic solvent in the presence of a copper catalyst and a base to obtain the asymmetric conjugated diyne compound (3): Y.sup.2—Z.sup.2—C≡C—C≡C—Z.sup.1—Y.sup.1. In addition, provided is a method for producing a Z,Z-conjugated diene compound by reducing the resulting asymmetric conjugated diyne compound, or the like.