Of 2-methylcyclohexanol

When planning the synthesis of a compound using an organometallic reagent or indeed any synthesis the best approach is to reason backward from the product This method is called retrosynthetic analysis Retro synthetic analysis of 1 methylcyclohexanol suggests it can be prepared by the reaction of methylmagnesmm bromide and cyclohexanone... 

Assume you are carrying out the dehydration of 1-methylcyclohexanol to yield L-methylcyclohexene. How could you use infrared spectroscopy to determine when the reaction is complete ... 

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. 

Tire acid-catalyzed dehydration of 1-methylcyclohexanol yields a mixture o( two alkenes. How could you use 1H NMR to help you decide which was which ... 

Because of the usefulness of the reaction, a number of ways have been devised for carrying out dehydrations. One method that works particularly well for tertiary alcohols is the acid-catalyzed reaction discussed in Section 7.1. For example, treatment of 1-methylcyclohexanol with warm aqueous sulfuric acid in a solvent such as tetrahydrofuran results in loss of water and formation of 1-methylcydohexene. 

Tertiary Alkyl Alcohols. Tertiary alkyl alcohols generally undergo facile reduction when treated with acids in the presence of organosilicon hydrides.127,136 This comparative ease of reduction reflects the enhanced stability and ease of formation of tertiary alkyl carbenium ions compared with primary and secondary carbenium ions. Thus, treatment of 1-methylcyclohexanol with mixtures of triethylsilane and aluminum chloride in dichloromethane produces near quantitative yields of methylcyclohexane with or without added hydrogen chloride in as little as 30 minutes at room temperature, in contrast to the more vigorous conditions needed for the reduction of the secondary alcohol cyclohex-anol.136... 

The reaction mixture is stirred at room temperature for 2 hours after which time the mercury is found as a shiny liquid. The supernatant liquid is separated from the mercury (Note 5), the ether layer is separated and the aqueous solution is extracted with two 100-ml. portions of ether. The combined ether solutions are dried over magnesium sulfate and distilled to give 24.1-25.8 g. (70.5-75.4%) of 1-methylcyclohexanol, b.p. 154.5-156° n21 D 1.4596 (Note 6). 

The distilled product slowly deposits mercury. In an effort to determine whether extent of this deposition is reduced by extending the time of reduction, the checkers found that stirring the crude alcohol with Celite for 15 hours, followed by filtration and distillation, did not diminish the amount of mercury deposited. However, in a typical run where the yield of distilled alcohol was 24.6 g. (72.0%), after standing for 24 hours, the distillate was decanted from the deposited mercury and redistilled to give 21.4 g. of 1-methylcyclohexanol which did not deposit mercury upon standing for one week at room temperature. The yield of twice-distilled alcohol was 02.6%. 

Methylcyclohexene is easily synthesized by the dehydration of 1-methylcyclohexanol. The most substituted alkene is the desired product. 

What products would you expect to obtain from reaction of 1-methylcyclohexanol with the following reagents ... 

Soluble resin 51, based on an acrylamide backbone, was also prepared by Berg-breiter, using an approach similar to that considered for 50. In this case the polymer is soluble in polar solvents. The presence of the azo dye (DFdye = 0.0002) is used to check that less than 0.1% of the resin remains in the solution after precipitation with hexanes. This catalyst was able to both catalyze efficiently the acetylation of 1-methylcyclohexanol to give 45 and afford BOC protection of phenols to prepare structures similar to 53 in DCM at room temperature (Scheme 10.11). These reactions required very low catalyst loadings (0.2-5 mol.%). No problems were found for the recycling of 51 [190]. 

Dialkylaminopyridine (DAAP) catalysts are effective catalysts for acylation reactions. The acetylation of 1- methylcyclohexanol by acetic anhydride in the presence of triethylamine (TEA) was used as a test reaction for the polymer-bond DAAP. The conversion of the starting alcohol was measured by GC analysis using ethyl benzene as an internal standard. The initial rates were studied and a first order analyses showed that the rate constant for reaction (1) was 0.178 h for 4-dimethylaminopyridine (DMAP), and 0.120 h for PNIPAM-DAAP-MR. 

Other disconnections of 1-methylcyclohexanol are possible because any bond to carbon can serve as a disconnection site. For example, one of the ring C—C bonds could be broken. However, these are not useful disconnections, because the synthetic... 

Problem 9.30. As pointed out in Scheme 9.74, methylenecyclohexane is the minor product of the dehydration of 1-methylcyclohexanol while 1-methylcyclohexene is the major product. Propose a synthesis of the former in which the latter might not be found at aU. 

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