Methylenecyclohexane oxide

Methylenecyclohexane oxide has been prepared by the oxidation of methylenecyclohexane with benzonitrile-hydrogen peroxide or with peracetic acid by treatment of 1-chlorocyclo-hexylmethanol with aqueous potassium hydroxide and by the reaction of dimethylsulfonium methylide with cyclohexanone. This reaction illustrates a general method for the conversion of ketones and aldehydes into oxiranes using the methylene-transfer reagent dimethyloxosulfonium methylide. The yields of oxiranes are usually high, and the crude products, in most cases, are of sufficient purity to be used in subsequent reactions (e.g., rearrangement to aldehydes) without further purification. 

Cyclic ketones. Diazomethane ring expansion of cyclohexanone gives cyclo-heptanone in yields as high as 63% and smaller amounts of cyclooctanone and methylenecyclohexane oxide. The cycloheptanone is easily separated from the... 

Methylenebis(triphenylphosphonium)-bromide, 446 Methylene blue, 201 Methylene bromide, 273 Methylene chloride, 69,72,79,180,273,398 Methylenecyclohexane, 226, 349 Methylenecyclohexane oxide, 171 1 a, 2a-Methylene-16a, 17a-(dimethyl-methylenedioxy)-A,s-pregnadiene-3, 20-dione, 172 Methylene iodide, 273, 371 Methylenemagnesium bromide (iodide), 273-274... 

Corey and Chaykovsky26 give a detailed description of the preparation of the reagent from trimethyloxosulfonium iodide, dimethyl sulfoxide, and sodium hydride, and for its reaction with cyclohexanone to form the oxirane methylenecyclohexane oxide. 

You might also recall from Section 12.7 that epoxides, cyclic ethers with a three-memhered ring, are unusually reactive in Sn2 processes because of angle strain. Methylenecyclohexane oxide, for instance, undergoes a base-induced Sn2 ring-opening on treatment with hydroxide ion at 100 °C. 

The procedure is a modification of that published. Methylenecyclohexane has been prepared by the pyrolysis of N,N-dimethyl-l-methylcyclohexylamine oxide, N,N,N-trimethyl-l-methylcyclohexylammonium hydroxide, N,N-dimethylcyclo-hexylmethylamine oxide, and N,N,N-trimethylcyclohexylmethyl-ammoniumhydroxide. It has also been obtained from the pyrolysis of cyclohexylmethyl acetate and of cyclohexylideneacetic acid and from the dehydrohalogenation of cyclohexylmethyl iodide. ... 

Does hydroboration/oxidation of methylenecyclohexane yield cyclohexyl-methanol or 1-methylcyclohexanol ... 

Figure 13.21 (a) The 1H NMR spectrum of cyclohexylmethanol, the product from hydroboration/oxidation of methylenecyclohexane, and (b) the 1H NMR spectrum of 1-methylcyclohexanol, the possible alternative reaction product. 

The present preparation of methylenecyclohexane is an example of an amine oxide pyrolysis. This route from amines to olefins in many cases yields pure olefins where the alternative method, the Hofmann exhaustive methylation reaction, is accompanied by some rearrangement to more stable isomeric olefins. 

It was established <2002T891> that in the presence of trifluoroacetophenone as trapping agent, the ozonolysis of 2,2,6-trimethyl-l-methylenecyclohexane afforded only the cross-ozonide derived from the capture of formaldehyde oxide, whereas the ozonolysis of 2,2,5-trimethyl-l-methylenecyclopentane gave only the alternative cross-ozonide derived from cycloadditions of 2,2,5-trimethylcyclopentanone oxide. 

Structure-Reactivity Relationship of Olefins. The relative reactivity of a series of olefins toward the potent oxidizing species, X, formed by the interaction of TPP Mn(II) with 02, was investigated by means of a competitive reaction technique. As shown in Table VII, the relative reactivity of an olefin, as followed by gas-liquid chromatographic determination, increases on introduction of an alkyl substituent onto the olefinic carbon atom other than the reacting carbon atom. However, the introduction of an alkyl substituent onto the reacting carbon atom reduces (or compensates) the accelerative electronic effect, as seen in the comparison between cyclohexene and n-hexene. This situation becomes clearer if one compares the two dialkyl ethylenes, cyclohexene and methylenecyclohexane, where the former has a single substituent on the reacting carbon and the other has none the observed relative reactivity is 1 27.2. 

An exception involves the passage of hot alcohol vapors over thorium oxide at 350-450°C, under which conditions Hofmann s mle is followed, and the mechanism is probably different. Cyclobutanol derivatives can be opened in the presence of a palladium catalyst. 2-Phenylbicyclo[3.2.0]octan-2-ol, for example, reacted with a catalytic amount of palladium acetate in the presence of pyridine and oxygen to give phenyl methylenecyclohexane ketone. ... 

The purpose of preparing aliphatic amine oxides is usually their thermal decomposition to cis alkenes and N,N-dialkylhydroxylamines (Cope rearrangement) [156, 161, 1187]. Thus A, A -dimethylcyclohexylmethylamine is oxidized with 30% hydrogen peroxide in methanol to its oxide, whose decomposition at 90-100 °C at 10 mm of Hg and at 160 °C for 2 h furnishes 79-88% of methylenecyclohexane and 78-90% of A, A -dimethylhydroxyl-amine [161], Another example is the preparation of cw-cyclooctene from dimethylcyclooctylamine (equation 502) [1187]. 

Amines oxides. Procedures for the preparation of an aliphatic amine (4), its conversion to the amine oxide (5), and pyrolysis of this to methylenecyclohexane (6, Cope reaction) are shown in the formulation. A homogeneous solution of 0.35... 

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