Background Art For 0-hydroxyhydroperoxide compounds derived from disubstituted olefin compounds such as cyclopentene and a-methylstyrene, it has already been known that aldehydes and ketones can be obtained by their thermal decomposition at high temperatures higher than 150°C (see, e. g, JP-A 58- <BR> <BR> 121234; Chem. Ber. , 129,1453 (1996) ). However, there has not been known a process for producing aldehydes and ketones by decomposing (3-hydroxy- hydroperoxide compounds derived from trisubstituted olefin compounds.

Disclosure of Invention Under these circumstances, the present inventors have intensively studied to develop a process for producing aldehydes and ketones by decom- posing (3-hydroxyhydroperoxide compounds derived from trisubstituted ole- fin compounds under mild conditions, and have found that the decomposition can easily proceed by reacting the 0-hydroxyhydroperoxide compound with a compound of an element of Group VIa, such as a molybdenum compound, to give a ketone and an aldehyde, thereby completing the present invention.

Thus the present invention provides a process for the production of an aldehyde of formula (2):

wherein R3 is as defined below, and a ketone of formula (3): wherein R'and R'are as defined below, which process comprises reacting a P-hydroxyhydroperoxide compound of formula (1) : wherein Rl, R2, and R3 are the same or different and independently substi- tuted or unsubstituted alkyl, substituted or unsubstituted aryl, substituted or unsubstituted aralkyl, substituted or unsubstituted acyl, substituted or unsubstituted alkoxycarbonyl, substituted or unsubstituted aryloxycarbonyl, substituted or unsubstituted aralkyloxyearbonyl or carboxyl; or R'and R, R' and R3, or R2 and R3 may be combined together to form a ring structure; and one of X and Y is hydroxyl and the other is hydroperoxy, with a compound of an element of Group VIa.

Mode for Carrying Out the Invention First of all, the following will describe (3-hydroxyhydroperoxide com- pound of formula (1) : wherein Rl, R2, and R3 are the same as defined above (hereinafter abbrevi- <BR> <BR> ated as (3-hydroxyhydroperoxide compound (1) ) as the starting material in the present invention.

The substituted or unsubstituted alkyl may include straight or branched chain, or cyclic alkyl groups of 1 to 20 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n- pentyl, n-decyl, n-undecyl, n-dodecyl, n-tridecyl, n-tetradecyl, n-pentadecyl,

n-hexadecyl, n-heptadecyl, n-octadecyl, n-nonadecyl, n-eicosyl, cyclopropyl, 2, 2-dimethylcyclopropyl, cyclopentyl, cyclohexyl, and menthyl, and alkyl groups substituted with alkoxy such as methoxy and ethoxy, aryloxy such as phenoxy, aralkyloxy such as benzyloxy, halogen such as fluorine and chlorine, acyl, alkoxycarbonyl, aryloxycarbonyl, aralkyloxycarbonyl, and carboxyl.

The alkyl groups substituted with such substituents may include chloro- methyl, fluoromethyl, trifluoromethyl, methoxymethyl, ethoxymethyl, me- thoxyethyl, methoxymethylcarbonyl, and 1-ethoxycarbonyl-2, 2-diemthyl-3- cyclopropyl.

The substituted or unsubstituted aryl may include phenyl and naph- thyl groups, and phenyl and naphthyl groups substituted with a substi- tuent (s), such as the above-mentioned alkyl, aryl, alkoxy, and aralkyl (e. g, benzyl, phenethyl), aryloxy (e. g, phenoxy, naphthoxy), aralkyloxy (e. g., ben- zyloxy, naphthylmethoxy), and halogen, which substituted phenyl and naph- thyl groups may include 2-methylphenyl, 4-chlorophenyl, 4-methylphenyl, 4- methoxyphenyl, and 3-phenoxyphenyl. The substituted or unsubstituted aralkyl may include those which are composed of the above-mentioned substituted or unsubstituted aryl and the above-mentioned alkyl, such as benzyl, 4-chlorobenzyl, 4-methylbenzyl, 4-methoxybenzyl, 3-phenoxybenzyl, 2,3, 5, 6-tetrafluorobenzyl, 2,3, 5,6-tetrafluoro-4-methylbenzyl, 2,3, 5,6-tetra- fluoro-4-methoxybenzyl, and 2,3, 5,6-tetrafluoro-4-methoxymethylbenzyl.

The substituted or unsubstituted acyl may include those which are composed of carbonyl and the above-mentioned substituted or unsubstituted alkyl, substituted or unsubstituted aryl, or substituted or unsubstituted aralkyl, such as methylcarbonyl, ethylcarbonyl, phenylcarbonyl, and benzyl- carbonyl.

The substituted or unsubstituted alkoxycarbonyl, the substituted or unsubstituted aryloxycarbonyl, and the substituted or unsubstituted aral-

kyloxycarbonyl may include those which are composed of carbonyl and the above-mentioned substituted or unsubstituted alkoxy, substituted or unsub- stituted aryloxy, or substituted or unsubstituted aralkyloxy, respectively, such as methoxycarbonyl, ethoxycarbonyl, phenoxycarbonyl, and benzyloxy- carbonyl.

The ring structure when such substituents are combined together to form a ring structure may include cyclopentane, cyclohexane, cyclopentene, and cyclohexene rings.

The (3-hydroxyhydroperoxide compound (1) may include 2-methyl-2- hydroperoxy-3-hydroxypentane, 3-methyl-3-hydroperoxy-2-hydroxyhexane, 1-methyl-1-hydroperoxy-2-hydroxycyclopentane, 1, 3-dimethyl-1-hydroper- oxy-2-hydroxycyclohexane, 1, 3, 5-trimethyl-1-hydroperoxy-2-hydroxycyclo- hexane, 3-hydroperoxy-4-hydroxycarene, methyl 3, 3-dimethyl-2- (2-methyl-2- hydroperoxy-l-hydroxypropyl) cyclopropanecarboxylate, ethyl 3,3-dimethyl- 2-(2-methyl-2-hydroperoxy-1-hydroxypropyl) cyclopropanecarboxylate, iso- propyl 3, 3-dimethyl-2-(2-methyl-2-hydroperoxy-1-hydroxypropyl) cyclopro- panecarboxylate, tert-butyl 3, 3-dimethyl-2-(2-methyl-2-hydroperoxy-1-hy- droxypropyl) cyclopropanecarboxylate, cyclohexyl 3, 3-dimethyl-2- (2-methyl- 2-hydroperoxy-1-hydroxypropyl) cyclopropanecarboxylate, menthyl 3,3-di- methyl-2- (2-methyl-2-hydroperoxy-l-hydroxypropyl) cyclopropanecarboxyl- ate, benzyl 3, 3-dimethyl-2-(2-methyl-2-hydroperoxy-1-hydroxypropyl) cyclo- propanecarboxylate, 4-chlorobenzyl 3, 3-dimethyl-2- (2-methyl-2-hydroper- oxy-l-hydroxypropyl) cyclopropanecarboxylate, 2,3, 5,6-tetrafluorobenzyl 3,3- dimethyl-2- (2-methyl-2-hydroperoxy-l-hydroxypropyl) cyclopropanecarboxyl- ate, 2,3, 5,6-tetrafluoro-4-methylbenzyl 3, 3-dimethyl-2- (2-methyl-2-hydroper- oxy-1-hydroxypropyl) cyclopropanecarboxylate, 2,3, 5,6-tetrafluoro-4-me- thoxymethylbenzyl 3, 3-dimethyl-2- (2-methyl-2-hydroperoxy-l-hydroxypro- pyl) cyclopropanecarboxylate, 3-phenoxybenzyl 3, 3-dimethyl-2- (2-methyl-2-

hydroperoxy-l-hydroxypropyl) cyclopropanecarboxylate, methyl 3,3-dimeth- yl-2- (2-methyl-2-hydroxy-l-hydroperoxypropyl) cyclopropanecarboxylate, ethyl 3, 3-dimethyl-2- (2-methyl-2-hydroxy-1-hydroperoxypropyl) cyclopro- panecarboxylate, isopropyl 3, 3-dimethyl-2- (2-methyl-2-hydroxy-l-hydroper- oxypropyl) cyclopropanecarboxylate, and tert-butyl 3, 3-dimethyl-2- (2-methyl- 2-hydroxy-1-hydroperoxypropyl) cyclopropanecarboxylate.

The (3-hydroxyhydroperoxide compound (1) may contain asymmetric carbon in the molecule and has optical isomers. Either individuals or mix- tures of the optical isomers can be used in the present invention.

These (3-hydroxyhydroperoxide compound (1) can be obtained by reacting trisubstituted olefin compound of formula (5): (hereinafter abbreviated as trisubstituted olefin compound (5)) wherein R', R2, and R3 are as defined above, with hydrogen peroxide in the presence of a tungsten oxide catalyst which is obtained by reacting a tung- sten compound such as tungsten metal with hydrogen peroxide. In the reaction of the trisubstituted olefin compound with hydrogen peroxide, the aldehyde of formula (2): wherein R3 is as defined above, the ketone of formula (3): wherein Rl and R2 are as defined above, and the diol of formula (6): wherein R', R2, and R3 are as defined above, can be obtained as by-products

in addition to the desired (3-hydroxyhydroperoxide compound (1); however, the p-hydroxyhydroperoxide compound (1) can be obtained with good selec- tivity by carrying out the reaction in the range of 0°C to 65°C.

The trisubstituted olefin compounds (5) may include 2-methyl-2-pen- tene, 3-methyl-2-hexene, 1-methylcyclopentene, 1, 3-dimethylcyclopentene, 1,3, 5-trimethylcyclohexene, 3-carene, methyl 3, 3-dimethyl-2- (2-methyl-l- propenyl) cyclopropanecarboxylate, ethyl 3, 3-dimethyl-2-(2-methyl-1-prope- nyl) cyclopropanecarboxylate, isopropyl 3, 3-dimethyl-2-(2-methyl-1-prope- nyl) cyclopropanecarboxylate, tert-butyl 3, 3-dimethyl-2-(2-methyl-l-prope- nyl) cyclopropanecarboxylate, cyclohexyl 3, 3-dimethyl-2-(2-methyl-1-prope- nyl) cylopropanecarboxylate, menthyl 3, 3-dimethyl-2- (2-methyl-l-propenyl)- cylopropanecarboxylate, and benzyl 3, 3-dimethyl-2- (2-methyl-l-propenyl)- cylopropanecarboxylate.

The trisubstituted olefin compound may contain asymmetric carbon and has optical isomers. Either individuals or mixtures of the optical iso- mers can be used.

Examples of the tungsten oxide catalyst used in the production of (3- hydroxyhydroperoxide compound (1) includes a tungsten oxide catalyst which is obtained by reacting tungsten metal or a compound thereof such as tungsten metal, tungsten boride, tungsten carbide, tungstic acid, tungsten oxide, or sodium tungstate with hydrogen peroxide. The amount of the tungsten oxide catalyst is a catalytic amount, preferably 0.001 mole, per mol of the trisubstituted olefin compound (5), and there is no particular upper limit thereof. From an economical point of view, the amount for their use is not more than 1 mole, per mol of the trisubstituted olefin compound (5).

For the hydrogen peroxide, an aqueous hydrogen peroxide solution is usually used, but a solution of hydrogen peroxide in an organic solvent may also be used. The amount of hydrogen peroxide that may be suitably used is

usually 2 moles, per mol of the trisubstituted olefin compound (5), and there is no particular upper limit thereof. From an economical point of view, the amount of hydrogen peroxide that may be suitably used is not more than 10 moles, per mol of the trisubstituted olefin compound (5).

After trisubstituted olefin compound (5) is reacted with hydrogen peroxide, and for example, 90% or more of the trisubstituted olefin compound (5) is converted, the reaction mixture may be, for example, subjected to treatment such as extraction, phase separation, concentration and/or column chromatography, if necessary, to isolate p-hydroxyhydroperoxide compound (1) as a major product from the reaction mixture, which are then used in the present invention. Alternatively, if necessary, water and/or a water-immis- cible organic solvent may be added to the reaction mixture, followed by extraction, and the resulting organic layer is concentrated to isolate P-hy- droxyhydroperoxide compound (1), which can be then used in the present in- vention. The isolated (3-hydroxyhydroperoxide compound (1) may be puri- fied by means such as column chromatography before use, if necessary.

Then, the following will describe a process for producing the aldehyde of formula (2): (hereinafter abbreviated as aldehyde (2)) wherein Rus ils as defined above, and the ketone of formula (3): (hereinafter abbreviated as ketone (3)) wherein Rl and R2 are as defined above, by reacting (3-hydroxyhydroperoxide compounds (1) with the compound of an element of Group VIa.

The reaction of (3-hydroxyhydroperoxide compound (1) with the com-

pound of an element of Group VIa causes cleavage of carbon-carbon bonds to give the aldehyde (2) and the ketone (3).

The metal or compound of an element of Group VIa may include a tungsten metal or a compound thereof such as a tungsten metal, tungsten oxide (e. g., W02, W03, W, 8049, W20°58, W60°l48, W40°ls9), tungstic acid, sodium tungstate, tungsten sulfide, tungsten boride, or tungstophosphoric acid; and a molybdenum metal or a compound thereof such as molybdenum metal, molybdenum oxide (e. g, MoO2, MoO3, Mo308, Mo8023, MogO26, Mo, 7047, Mo5OI4), molybdic acid, potassium molybdate, sodium molybdate, ammonium molybdate, molybdenum chloride, molybdenum sulfide, dioxobis (acetylace- tonato) molybdenum, molybdenum hexacarbonyl, or molybdophosphoric acid.

In these metals and compounds, molybdenum metal or compounds are preferred. These metals or compounds of elements of Group VIa may be used alone or in combination. Typical compounds of elements of Group VIa that may be suitably used are not peroxotungstate or peroxomolybdate as may be used in the production process of (3-hydroxyhydroperoxide compound (1).

The amount of the metal or compound of an element of Group VIa that may be suitably used is catalytic and preferably 0.001 mole, per mol of the p-hydroxyhydroperoxide compound (1), and there is no particular upper limit thereof. From an economical point of view, the amount of the metal or compound of an element of Group VIa that may be suitably used is usually not more than 1 mole, per mol of the (3-hydroxyhydroperoxide compound (1).

The reaction of P-hydroxyhydroperoxide compound (1) with the metal or compound of an element of Group VIa may be achieved by mixing both of them. The reaction temperature for the present reaction is usually 0°C to 120°C, preferably 20°C to 100°C.

The present reaction is usually carried out in a solvent which dis-

solves P-hydroxyhydroperoxide compound (1). The solvent may include water, an organic solvent and a mixture of water and an organic solvent.

Examples of the organic solvent include, for example, alcohol solvents such as methanol, ethanol, and tert-butanol; nitrile solvents such as acetonitrile and propionitrile; ether solvents such as diethyl ether, methyl tert-butyl ether, and tetrahydrofuran; ester solvents such as ethyl acetate; aromatic hydrocarbon solvents such as toluene and xylene; and halogenated hydro- carbon solvents such as dichloromethane, dichloroethane, chloroform, carbon tetrachloride, chlorobenzene, and dichlorobenzene. The amount of the solvent is such that p-hydroxyhydroperoxide compound (1) can be dissolved, and there is no particular upper limit thereof From the viewpoint of volume efficiency or the like, the amount of the solvent is usually not more than 100 parts by weight, per 1 part by weight of the R-hydroxyhydroper- oxide compound (1).

To make the reaction proceed more smoothly, phase transfer cata- lysts such as trioctylmethylammonium hydrogensulfate and tetrabutyl- ammonium chloride may be used.

The present reaction may be carried out under normal pressure con- ditions or under pressurized conditions. The progress of the reaction can be monitored by ordinary means of analysis, such as high-pressure liquid chro- matography, thin layer chromatography, nuclear magnetic resonance spec- trometry, and infrared absorption spectrometry.

After completion of the reaction, for example, the reaction mixture is subjected to concentration and column chromatography, so that the ketone and the aldehyde can be separated and isolated from the reaction mixture.

Alternatively, if necessary, water and/or a water-immiscible organic solvent is added to the reaction mixture, followed by extraction, and the resulting organic layer is subjected to extraction, phase separation, and/or concen-

tration, so that these products can be separated and isolated. The isolated ketone and aldehyde can be further separated and purified by means such as distillation and column chromatography, if necessary.

The water-immiscible organic solvent may include aromatic hydro- carbon solvents such as toluene and xylene; halogenated hydrocarbon sol- vents such as dichloromethane, chloroform, and chlorobenzene; ether sol- vents such as diethyl ether, methyl tert-butyl ether, and tetrahydrofuran; and ester solvents such as ethyl acetate. The amount of the water-immisci- ble organic solvent is not particularly limited.

For example, when (3-hydroxyhydroperoxide compound (1) obtained by reacting trisubstituted olefin compound (5) with hydrogen peroxide can be used as the starting material in the present reaction, they may be used while containing the diol of formula (6) formed as a by-product in the reaction of trisubstituted olefin compound (5) with hydrogen peroxide. The diol of formula (6) cause almost no decomposition, even if treated with a compound of an element of Group VIa, and remain in the reaction mixture. Therefore, for example, when a mixture of P-hydroxyhydroperoxide compound (1) and a diol of formula (6) may be used as the starting materials in the present in- vention, the reaction mixture after completion of the reaction may be treated <BR> <BR> with, for example, sodium periodate (e. g, Tetrahedron, 53,16277 (1997) ), so that the diol of formula (6) can be decomposed and converted into the alde- hyde (2) and the ketone (3).

The aldehyde (2) and ketone (3) can be separated to isolate either the aldehyde (2) or ketone (3) by a separation step, if necessary, such as distil- lation, crystallization, and/or column chromatography.

The aldehyde (2) thus obtained may include acetaldehyde, propion- aldehyde, butylaldehyde, pentylaldehyde, benzaldehyde, 5-oxohexylaldehyde, 2-methyl-5-oxohexylaldehyde, 4-methyl-5-oxohexylaldehyde, 3-methyl-5-

oxohexylaldehyde, 2, 4-dimethyl-5-oxohexylaldehyde, 3, 4-dimethyl-5- oxohexylaldehyde, 2, 3-dimethyl-5-oxohexylaldehyde, 2,3, 4-trimethyl-5-oxo- hexylaldehyde, 6-oxoheptylaldehyde, 2-methyl-6-oxoheptylaldehyde, 4- methyl-6-oxoheptylaldehyde, 2,4-dimethyl-6-oxoheptylaldehyde, 2,3-dimeth- yl-6-oxoheptylaldehyde, 3,4-dimethyl-6-oxoheptylaldehyde, 2,3, 4-trimethyl- 6-oxoheptylaldehyde, 2, 2-dimethyl-3- (2-oxopropyl) cyclopropaneacetaldehyde, 2, 2-dimethyl-3- (3-oxobutyl) cyclopropylaldehyde, 2, 2-dimethyl-3- (2-oxoethyl)- cyclobutaneacetaldehyde, methyl 3, 3-dimethyl-2-formylcyclopropanecarbox- ylate, ethyl 3, 3-dimethyl-2-formylcyclopropanecarboxylate, isopropyl 3,3-di- methyl-2-formylcyclopropanecarboxylate, tert-butyl 3, 3-dimethyl-2-formyl- cyclopropanecarboxylate, cyclohexyl 3, 3-dimethyl-2-formylcyclopropanecar- boxylate, menthyl 3, 3-dimethyl-2-formylcyclopropanecarboxylate, benzyl 3, 3-dimethyl-2-formylcyclopropanecarboxylate, 4-chlorobenzyl 3,3-dimethyl- 2-formylcyclopropanecarboxylate, 2,3, 5,6-tetrafluorobenzyl 3,3-dimethyl-2- formylcyclopropanecarboxylate, 2,3, 5, 6-tetrafluoro-4-methylbenzyl 3,3-di- methyl-2-formylcyclopropanecarboxylate, 2,3, 5, 6-tetrafluoro-4-methoxyben- zyl 3, 3-dimethyl-2-formylcyclopropanecarboxylate, 2,3, 5, 6-tetrafluoro-4-me- thoxymethylbenzyl 3, 3-dimethyl-2-formylcyclopropanecarboxylate, and 3- phenoxybenzyl 3, 3-dimethyl-2-formylcyclopropanecarboxylate.

The ketone (3) may include acetone, methyl ethyl ketone, diethyl ketone, methyl propyl ketone, and acetophenone.

Examples The present invention will hereinafter be further illustrated by the following Examples; however, the present invention is not limited to these Examples. The analysis was carried out by gas chromatography (herein- after abbreviated as GC) and high-pressure liquid chromatography (herein- after abbreviated as LC), and the respective conditions for GC analysis and

LC analysis are as follows: <Conditions for GC analysis> Column: DB-1 (+ 0.25 um x 30 m, film thickness 1.0 am) Carrier gas: helium (flow rate: 1 m/min.) Split ratio: 1/10 Sample input: 1, uL Column temperature: 100°C (0 min.) 180*C (programming rate: 2°C/min. ; retention time at 180°C : 0 min.) 300*C (programming rate: 10°C/min. ; retention time at 300°C : 15 min.) Inlet temperature: 200°C Detector temperature: 250°C <Conditions for LC analysis> Column: SUMIPAX ODS A-212 (5 lem, + 6 mm x 15 cm) Mobile phase: A solution, 0.1 vol. % aqueous trifluoroacetic acid solution B solution, 0.1 vol. % trifluoroacetic acid solution in acetonitrile The composition is changed linearly for 40 minutes from A solution/B solution = 90/10 (volume ratio) to A solution/B solution = 10/90 (volume ratio), and retained at the composition rate of A solution/B solution = 90/10 (volume ratio).

Flow rate: 1.0 mL/min.

Sample input: 10, uL Detection wavelength: 220 nm Reference Example 1 A 2-L four-neck flask equipped with a stirrer and a reflux condenser was charged with 10 g of tungsten metal powder and 75 g of water, to which

36.7 g of 60 wt. % aqueous hydrogen peroxide solution was added dropwise at an internal temperature of 40°C while stirring over 1 hour, followed by stir- ring at the same temperature for another 1 hour to effect reaction, giving a uniform solution containing tungsten oxide. The flask was then charged with 6.8 g of boric acid, and the solution was cooled to room temperature, followed by charging 380 g of tert-butyl alcohol and 19 g of 60 wt. % aqueous hydrogen peroxide solution. The flask was then charged with 133 g of anhydrous magnesium sulfate, followed by stirring at an internal tempera- ture of 20°C for another 2 hours. To the slurry solution thus obtained were added dropwise simultaneously a mixed solution consisting of 100 g of methyl trans-3, 3-dimethyl-2- (2-methyl-1-propenyl) cyclopropanecarboxylate and 120 g of tert-butyl alcohol, and 41 g of 60 wt. % aqueous hydrogen per- oxide solution, followed by stirring at an internal temperature of 20°C for 18 hours to effect reaction. Then, 600 g of water was added, and extraction with 500 g of toluene was repeated twice to give 1688 g of a toluene solution.

The LC analysis of the toluene solution showed that methyl trans-3,3-di- methyl-2- (l-hydroxy-2-hydroperoxy-2-methylpropyl) cyclopropanecarboxyl- ate and methyl trans-3, 3-dimethyl-2- (1-hydroperoxy-2-hydroxy-2-methylpro- pyl) cyclopropanecarboxylate (these two compounds will hereinafter be col- lectively abbreviated as the 0-hydroxyhydroperoxide compounds) as well as methyl 3, 3-dimethyl-2-formylcyclopropanecarboxylate were contained.

In the GC analysis of the toluene solution, the-hydroxyhydroper- oxide compounds were thermally decomposed at the inlet part and detected as methyl trans-3, 3-dimethyl-2-formylcyclopropanecarboxylate. Therefore, the yields of P-hydroxyhydroperoxide compounds and methyl trans-3,3-di- methyl-2-formylcyclopropanecarboxylate were calculated using both the GC analysis and the LC analysis.

The content for P-hydroxyhydroperoxide compounds in the toluene

solution was 4.5% and the yield was 60%. The content for methyl trans- 3, 3-dimethyl-2-formylcyclopropanecarboxylate in the toluene solution was 0.1% and the yield was 2.4%.

Example 1 To 300 g of the toluene solution containing the ß-hydroxyhydroper- oxide compounds obtained in the above Reference Example 1 was added 0.1 g of dioxobis (acetylacetonato) molybdenum, and the mixture was stirred at the reflux temperature for about 10 hours to effect reaction. From the reaction mixture, insoluble matter was removed by filtration while washing with tol- uene, and the filtrate obtained was partly concentrated under reduced pres- sure to give 264 g of a toluene solution containing methyl trans-3,3-dimeth- yl-2-formylcyclopropanecarboxylate. The GC analysis of the toluene solu- tion showed that the content for methyl trans-3, 3-dimethyl-2-formylcyclo- propanecarboxylate was 3.4% and the yield was 94% (on the basis of the hydroxyhydroperoxide compounds).

Example 2 A 100-mL four-neck flask equipped with a stirrer and a reflux con- denser was charged with 79 g of the toluene solution containing the ß-hy- droxyhydroperoxide compounds obtained in the same manner as described in Reference Example 1 (the content for the (3-hydroxyhydroperoxide com- pounds: 4.1% and the content for methyl trans-3, 3-dimethyl-2-formylcyclo- propanecarboxylate : 0.15%), 1 g of water, and 0.13 g of molybdenum sulfide powder, followed by reflux while stirring for 7 hours to effect reaction. The mixture was cooled, and insoluble matter was removed by filtration to give 78 g of a toluene solution containing methyl trans-3, 3-dimethyl-2-formyl- cyclopropanecarboxylate. The GC analysis of the toluene solution showed that the content for methyl trans-3,3-dimethyl-2-formylcyclopropanecarbox- ylate was 3.0% and the yield was 99% (on the basis of the ß-hydroxyhydro-

peroxide compounds).

Example 3 First, 80 g of the toluene solution containing the ß-hydroxyhydroper- oxide compounds (the content for the (3-hydroxyhydroperoxide compounds: 4.1% and the content for methyl trans-3, 3-dimethyl-2-formylcyclopropane- carboxylate: 0.15%), 1 g of water, and 0.22 g of molybdenum chloride powder were charged, and the mixture was refluxed while stirring for 7 hours to effect reaction. After cooling, insoluble matter was removed by filtration to give 78 g of a toluene solution containing methyl trans-3, 3-dimethyl-2-for- mylcyclopropanecarboxylate. The GC analysis of the toluene solution showed that the content for methyl trans-3, 3-dimethyl-2-formylcyclopro- panecarboxylate was 2.4% and the yield was 80% (on the basis of the ß-hy- droxyhydroperoxide compounds).

Example 4 A 300-mL flask equipped with a stirrer and a reflux condenser was charged with 15 g of water and 2 g of tungsten metal powder, to which 7.4 g of 60 wt. % aqueous hydrogen peroxide solution was added dropwise at an internal temperature of 40°C while stirring over 20 minutes, followed by stirring at the same temperature for 1 hour to effect reaction, giving a tung- sten oxide-containing solution. The solution was charged with 1.36 g of boric acid, and the mixture was cooled to room temperature, which was charged with 76 g of tert-butyl alcohol, 2 g of 60 wt. % aqueous hydrogen per- oxide solution, and 26.6 g of anhydrous magnesium sulfate, followed by stir- ring at room temperature for another 1.5 hours. To the slurry solution ob- tained were added dropwise simultaneously a mixed solution consisting of 20 g of methyl trans-3, 3-dimethyl-2-(2-methyl-1-propenyl) cyclopropanecarbox- ylate and 24 g of tert-butyl alcohol, and 10 g of 60 wt. % aqueous hydrogen peroxide solution over 4 hours, followed by stirring at an internal tempera-

ture of 15°C for 24 hours to effect reaction. Then, 120 g of water was added, and extraction with 100 g of toluene was repeated twice to give 331 g of a toluene solution containing the P-hydroxyhydroperoxide compounds and methyl trans-3, 3-dimethyl-2- (1, 2-dihydroxy-2-methylpropyl) cyclopropane- carboxyalte.

To 315 g of the toluene solution was added 1.1 g of dioxobis (acetyl- acetonato) molybdenum, followed by stirring at the reflux temperature for 6 hours to effect reaction. From the reaction mixture, insoluble matter was removed by filtration while washing with toluene to give a solution contain- ing methyl trans-3, 3-dimethyl-2-formylcyclopropanecarboxylate and methyl trans-3, 3-dimethyl-2- (1, 2-dihydroxy-2-methylpropyl) cyclopropanecarboxyl- ate.

To the solution was added dropwise 32 g of 15 wt. % aqueous sodium periodate solution at room temperature over 10 minutes, followed by stirring for 1 hour and holding. From the reaction mixture, insoluble matter was removed by filtration while washing with toluene, followed by phase separa- tion to give an organic layer. The organic layer was partly concentrated at room temperature under reduced pressure, and then washed with 100 g of 5 wt. % aqueous sodium thiosulfate solution, with 50 g of 5 wt. % aqueous sodi- um hydrogencarbonate, and further with 50 g of water to give 223 g of a tol- uene solution containing methyl trans-3, 3-dimethyl-2-formylcyclopropance- carboxylate. As the result of GC analysis, the yield of methyl trans-3,3-di- methyl-2-formylcyclopropanecarboxylate on the basis of methyl trans-3,3-di- methyl-2- (2-methyl-l-propenyl) cyclopropanecarboxylate was 74%.

Industrial Applicability According to the present invention, the reaction of P-hydroxyhydro- peroxide compounds of formula (1) with compounds of elements of Group VIa can give the corresponding aldehydes and ketones under mild conditions, and therefore, the process of the present invention is industrially advanta- geous.