2-METHYLCYCLOHEXANONE: CYCLOHEXANONE, 2-METHYL

Benzyl-6-methylcyclohexanone Cyclohexanone, 2-benzyl-6-methyl-(8) Cyclohexanone, 2-methyl-6-(phenylmethyl)- (9) (24785-76-0) 2-Methylcyclohexanone Cyclohexanone, 2-methyl- (8,9) (583-60-8) Diisopropylamine (8) 2-Propanamine, N-(l-methylethyl)- (9) (108-18-9) Butyllithium Lithium, butyl- (8,9) (109-72-8)... 

REGIOSELECTIVE MONOALKYLATION OF KETONES VIA THEIR MANGANESE ENOLATES 2-BENZYL-6 METHYLCYCLOHEXANONE FROM 2-METHYLCYCLOHEXANONE (Cyclohexanone, 2-methyl-6-(phenylmethyl)-)... 

Using the 3 mm. by 2 m. gas chromatography column described above, a mixture of stereoisomers of 2-allyl-5-methylcyclohexanone [Cyclohexanone, 5-methyl-2-(2-propenyl)-], prepared by allylation of the enamine of 3-methylcyclohexanone,7a showed peaks at retention times of 8.4 minutes (more stable isomer) and 9.6 minutes. A mixture of the two isomeric 2-allyl-3-methylcyclohexanones and the two isomeric 2-allyl-5-methylcyclohexanones clearly exhibited four distinct peaks on gas chromatography. 

Synonyms AI3-15915 BRN 0506751 EINECS 209-513-6 Methylanon a-Methylcyclohexa-none 2-Methylcyclohexanone 2-Methyl-l-cyclohexanone NSC 524 Sexton B Tetrahydro-o-cresol UN 2297. 

Benzyl-2-methylcyclohexanone Cyclohexanone, 2-benzyl-2-methyl- Cyclohexanone, 2-methyl-2-(phenylmethyl)- (1206-21-9), 76, 244... 

Ammoxidation of cyclic ketones over titanium silicates TS-1 has been performed.38 The reactivity of the cyclohexanones and methylcylcohexanones over TS-1 followed the order cyclohexanone > 2-methylcyclohexanone = 3-methyl-cyclohexanone > 2,6-dimethylcyclohexanone, reflecting the difference in the... 

Conjugate addition reactions, including the Robinson annulation, which make use of reactive Michael acceptors such as methyl vinyl ketone, can suffer from low yields of the desired adduct. The basic conditions required for enolate formation can cause polymerization of the vinyl ketone. Further difficulties arise from the fact that the Michael adduct 42 and the original cyclohexanone have similar acidities and reactivities, such that competitive reaction of the product with the vinyl ketone can ensue. These problems can be minimized by the use of acidic conditions. Sulfuric acid is known to promote the conjugate addition and intramolecular aldol reaction of 2-methylcyclohexanone and methyl vinyl ketone in 55% yield. Alternatively, a silyl enol ether can be prepared from the ketone and treated with methyl vinyl ketone in the presence of a Lewis acid such as a lanthanide triflate" or boron tri fluoride etherate (BF3 OEt2) and a proton source to effect the conjugate addition (followed by base-promoted aldol closure). 

Cyclohexanone, 4-(1,1-dimethylpropyl)-. See Isopentylcyclohexanone Cyclohexanone iso-oxime. See Caprolactam Cyclohexanone, isopentyl-. See Isopentylcyclohexanone Cyclohexanone, methyl-. See Methylcyclohexanone... 

Methyl carbon shieldings also offer conformational insight in cyclohexanones. In cis-3,5-dimethyl- and 3,3,5-trimethyl-cyclohexanones the equatorial 3-methyl carbon absorbs at ca. 22.3 p.p.m. whereas an equatorial 2-methyl carbon experiences an upfield shift to 14.6 p.p.m. ascribed to a y-interaction between methyl and oxygen. From related compounds these shifts have been estimated as 19.3 and 17.4 p.p.m. respectively. In the former case the upfield shift of 3 p,p.m. is less than the corresponding cyclohexane value on account of the smaller number of syn-axial interactions. In 3-methylcyclohexanone the methyl shielding indicates about 10% axial methyl conformer, corresponding to —AG of ca. 1.3 kcal mol . In cis-2,5-dimethylcyclo-hexanone (67) the observed methyl shieldings of 15.3 and 19.8 p.p.m. are in accord with an equilibrium which contains ca. 80% (67a). 

The enamines derived from cyclohexanones are of particular interest. The pyrrolidine enamine is most frequently used for synthetic applications. The enamine mixture formed from pyrrolidine and 2-methylcyclohexanone is predominantly isomer 17.106 A steric effect is responsible for this preference. Conjugation between the nitrogen atom and the tt orbitals of the double bond favors coplanarity of the bonds that are darkened in the structures. In isomer 17 the methyl group adopts a quasi-axial conformation to avoid steric interaction with the amine substituents.107 A serious nonbonded repulsion (A1,3 strain) in 18 destabilizes this isomer. 

The anion of cyclohexanone /V,/V-dimclhyl hydrazone shows a strong preference for axial alkylation.122 2-Methylcyclohexanone N,N-dimethylhydrazonc is alkylated by methyl iodide to give d.v-2,6-dimclhylcyclohcxanone. The 2-methyl group in the hydrazone occupies a pseudoaxial orientation. Alkylation apparently occurs anti to the lithium cation, which is on the face opposite the 2-methyl substituent. 

Methyl-l-cyclohexanone, see o-Methylcyclohexanone a -Methylcyclohexene, see 1-Methylcyclohexene 1-Methyl-l-cyclohexene, see 1-Methylcyclohexene Methyl 3-(dimethoxyphosphinyloxy)crotonate, see... 

A simple Sn2 alkylation reaction serves as example. As we have already seen, treating cyclohexanone with LDA gives the enolate anion, which can then be allowed to react with methyl iodide to give 2-methylcyclohexanone. 

Alternatively, cyclohexanone may initially be transformed into an enamine with a secondary amine, here pyrrolidine. This intermediate enamine can act as a nucleophile and can be alkylated at the P-position using methyl iodide. Finally, 2-methylcyclohexanone may be generated by hydrolysis of the iminium system, effectively a reversal of enamine formation. This gives us two routes to 2-methylcyclohexanone, a short process using the very strong base LDA and... 

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