2- Methylcyclohexanol, reaction with

In addition to the present method,2 1-amino-1-methylcyclo-hexane has been synthesized by the following procedures Ritter reaction, e.g., with 1-methylcyclohexanol (76%, 67%)3i 4 or 1-methylcyclohexene (35%,) 4 5 Hofmann reaction with 1-methyl-cyclohexanecarboxamide (80% as hydrochloride) 6 reduction of 1-methyl-l-nitrocyclohexane (63%) 6 Schmidt reaction with 1-methylcyclohexanecarboxylic acid (42%).6... 

Contrary to the case of anionic reactions, the formation of a strong proton-bound dimer for alcohols suggests that nucleophilic displacement may actually involve a frontside attack. Recent experiments carried out at atmospheric pressure by Speranza and Angelini (1980) using radiolytic techniques with isolation and glc analysis of neutral products reveal some interesting stereochemistry. For example, the reaction of protonated epoxy-rra/is-but-2-ene with H20 results in 98% inversion of configuration, while a similar reaction with cis-1 -chloro-4-methylcyclohexane results in approximately 80% of tro/is-4-methylcyclohexanol. With the high pressures utilized and with the possible participation of cluster ions a likelihood in this case, the data are consistent with a Walden inversion for these cases. 

When racemic 3-methyl-2-cyclohexenol is hydrogenated by the BINAP-Ru catalyst at 4 atm H2, trcms- and cis-3-methylcyclohexanol are produced in a 300 1 ratio (Scheme 33). The reaction with the (/ )-BINAP complex affords the saturated R,3R trans alcohol in 95% ee in 46% yield and unreacted S allylic alcohol in 80% ee with 54% recovery. 

The chirality present at the sulfur atom of, for example, p-tolylsulfinyl carbanion leads to the formation of a diastereoisomeric mixture of y-hydroxy sulfoxides on reaction with prochiral epoxides (Scheme 87). This reaction, coupled with the efficient desulfurization of the resulting sulfoxide by Raney nickel, has been used ingeniously for the enantioselective synthesis of rra j-2-methylcyclohexanol from epoxycyclohexane and (H-)-p-tolylsulfinylmethyllithium (Scheme 87). 

The reaction of HX with a tertiary alcohol is so rapid that it s often carried out simply by bubbling the pure HC1 or HBr gas into a cold ether solution of the alcohol. 1-Methylcyclohexanol, for example, is converted into l-chloro-1-methylcyclohexane by treating with HC1. 

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. 

The geometry of the cis-alkylcyclohexanol is favorable for trans elimination since the hydroxyl and the neighboring trans hydrogen are coplanar, but this is not true for the l,i-trans isomer hence the molecular conformation has to flip over, to set the hydroxyl group in the axial position for the trans elimination to occur. This would require a few kilocalories of energy and for frans-lert-butylcyclohexanol it would be more difficult to achieve than for IroMs-methylcyclohexanol. It is, therefore, possible that the trans elimination from a boat conformation, or possibly even an epimerization from the trans to the cis isomer which then undergoes a trans elimination reaction. Such an epimerization was found to occur under conditions of dehydration of certain alcohols over alumina, as will be seen under 1,4-cyclohexanediol. The more facile elimination of the cis-i-tert-butylcyclohexanol system as compared with the trans system in solution was also reported in the literature 63). 

Asymmetric ring-opening of saturated epoxides by organocuprates has been studied, but only low enantioselectivities (< 15% ee) have so far been obtained [49, 50]. Muller et al., for example, have reported that the reaction between cyclohexene oxide and MeMgBr, catalyzed by 10% of a chiral Schiff base copper complex, gave trans-2-methylcyclohexanol in 50% yield and with 10% ee [50]. 

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). 

This method of preparing alcohols is an adaptation of an oxymercuration procedure of Sand and Genssler2 and reduction methods of Henbest and Nicholls.3 Other methods for preparing 1-methylcyclohexanol are oxymercuration followed by reduction in tetrahydrofuran-water 4 reaction of cyclohexanone with... 

The mechanism of oxidation of alkanes with dimethyldioxirane has been examined by measurement of the primary kinetic isotope effect for the oxidation of cyclohexane and methylcyclohexane in solution and in the gas phase. These experiments indicated that the major products (cyclohexanol and methylcyclohexanol) are probably formed via an electrophilic oxygen-insertion reaction while minor by-products may arise from radical reactions.90... 

The first production stage is effected in a series of closed enamelled iron kettles filled with a mixture of equivalent amounts of 2-ethylanthraquinone and 2-ethylanthrahydroquinone dissolved in benzene and methylcyclohexanol oxygen is injected into the liquid through a porous filter while the temperature is maintained at 30 and 37 °C. The reaction may be symbolized as follows ... 

Diastereoselective reduction of ketones. Trialky Isilanes can reduce aldehydes and ketones in the presence of a catalytic amount of tetrabutylammonium fluoride in HMPT cf. reductions with activated hydrosilanes, II, 554). Under these conditions esters and nitriles are not reduced. The reaction is stereoselective. Thus 2-methylcyclohcxanone is reduced selectively to cA-2-methylcyclohexanol the cvT-selectivity depends on the bulkiness of the hydrosilanc, being highest (95%) with triphenylsilane. 

Draw the organic product(s) formed when 1-methylcyclohexanol is treated with each reagent. In some cases no reaction occurs. 

In addition to the present method, 1-amino-1-methylcyclo-hexane has been synthesized by the following procedures Ritter reaction, e.g., with 1-methylcyclohexanol (76%, 67%) or... 

P4-22g Alkylated cyclohexanols are important intermediates in the fragrance and perfume industry [Jnd. Eng. Chem. Res., 28, 693 (1989)]. Recent work has focused on gas-phase catalyzed hydrogenation of o-cresol to 2-methylcyclo-hexanone, which is then hydrogenated to 2-methylcyclohexanol, In this problem we focus on only the first step in the reaction (Figure P4-22). The reaction on a nickel-silica catalyst was found to be zero-order in o-cresol and first-order in hydrogen with a specific reaction rate at 170°C of 1.74 mol of o-cresol/(kg cat - min - atm). The reaction mixture enters the packed-bed reactor at a total pressure of 5 atm. The molar feed consists of 67% Hj and 33% o-creso at a total molar rate of 40 mol/min. 

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

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