Cyclohexyl carbinol

Statt dessen werden in einer Radikalreaktion 30% des Dimethyl-cyclohexyl-carbinols (43) gebildet. 

Cyclohexyl carbinol (6, 22), The amount of cyclohexyl bromide indicated in line 6 should be 163 g. (1 mole),... 

Cyclohexyl Carbinol, 6,22 Cyclohexyl chloride, 6, 24 Cyclohexylmagnesium bromide, 6, 20 Cyclohexylmagnesium chloride, 6, 24 3-Cyolouexyl Propine-i, 6, 26 C.yolopentanone, 5, 37 1-Cystine, 5, 29... 

FIGURE 2.15 (a) The IR spectrum of an alcohol (cyclohexyl-carbinol) in a dilute solution shows the sharp absorption of a free" (non-hydrogen-bonded) hydroxyl group at 3600 cm", (b) The IR spectrum of the same alcohol as a concentrated solution shows a broad hydroxyl group absorption at 3300 cm" due to hydrogen bonding. (Reprinted with permission... 

A mixture of cis- and trans-1,3- and l,4-bis-(hydroxymethyl)-cyclo-hexane (52 48) in 70% yield was obtained in methanol at 180 °C. 11 % of the starting material was hydrogenated to cyclohexyl carbinol. 

Alcohol/ cyclohexene Dicyclohexyl- ketone Yield (mole %) Cyclohexyl-carbinol Ester... 

The reduction of hydroxylamine by titanous salts in water produces the free amino radical, a reaction analogous to the formation of triphenylmethyl from the carbinol and a reducing agent.138 The amino radical will attack benzene to give diaminocyclohexadiene and di-(aminocyclohexadienyl) it converts cyclohexene into cyclohexyl-amine.139... 

Early studies of the asymmetric reduction of prochiral ketones by chiral aluminum alkoxides have been reviewed by Morrison and Mosher (1). Doering and Young (123) reported the reduction of methyl cyclohexyl ketone with chiral 3-methyl-2-butanol in the presence of a catalytic amount of aluminum alkoxide to give the (S)-( + )-carbinol in a 22% optical yield. Jackman and co-workers (124) similarly reduced methyl n-hexyl ketone with chiral 3,3-dimethyl-2-butanol to the (S)-( - )-carbinol in a 6% optical yield. Other attempts resulted in similar low optical yields or gave only racemic products. Since the reductions were carried out under equilibrium conditions, racemization could have accounted for the low optical yields. 

The product may be analyzed by use of a gas chromatography column packed with either LAC-728 (diethylene glycol succinate) or Carbowax 20M suspended on Chromosorb P. Using a 2.5-m. LAC-728 column heated to 100°, the submitters found retention times of 9.4 and 13.0 minutes for cyclohexyl methyl ketone and cyclohexyldimethylcarbinol. Less than 1% of the carbinol by-product was present. 

Epoxidation of prochiral dialkenyl carbinols 28 provides the anti-epoxide 29 of extremely high optical purity [68, 69, 70]. The first epoxidation occurs in an enantiotopic selective manner while the second one proceeds in an enantiomer-differentiating manner (kinetic resolution). In the second step, the minor (R)-monoepoxides 30 are consumed faster than the major (S)-enantiomers 29 and therefore the enantiomeric excess of the major anfi-monoepoxide 29 increases as the reaction proceeds. If a reaction proceeds with a kfas(/ksio, =104, anti-syn selectivity for the fast reaction=98 2 and for the slow reaction=38 62, as observed in the epoxidation of racemic ( )-l-cyclohexyl-2-buten-l-ol,the enantiomeric excess of anti-29 on calculation is 99.4,99.96, and 99.994% ee at 50,99, and 99.9% conversion, respectively. Yields of anti-29 are 48,93 (maximum), and 91% at the respective conversions. Actually, in the epoxidation of 1,4-pentadien-... 

The absolute control of configuration at the carbinol carbon of [5-methyl-2-(l-methyl-l-phenylelhyl)cyclohexyl] 2-hydroxy-4-octenoate (Table 4, entry 2), was determined to be S by conversion of the ene reaction product by reduction with diisobutylaluminum hydride to... 

Carbinol carbon shieldings of some cyclohexyl systems of the form CIS and tram 4—R—C Hjo—ORshifts given in p.p.m. from CS2... 

D isomer. See Carbetamide Phenylethyl carbinol. See Hydrocinnamic alcohol 1-Phenyl-1-propanol Phenylethyl cinnamate 2-Phenylethyl cinnamate. See Phenethyl cinnamate Phenyl ethyl cyclohexyl ether. See Cyclohexyl phenethyl ether... 

Citronellal p-Citronellol Cyclohexyl acetate Cyclohexylethyl acetate Decanal Dihydro-3-ionone Dimethyl phenethyl carbinol Ethyl butyrate Ethyl caproate Ethylene brassylate... 

Cram s model does not always predict the stereochemical result of kinetically controlled reductions with aluminum isopropoxide (Cram and Greene, 1953). For example, i -(—)-3-cyclohexyl-2-butanone is reduced to predominantly ZR,2R-erythro carbinol (erythro/threo = 1.9). Apparently special steric forces are important in this reduction. Recent work (Shiner and Whittaker, 1963) has shown that aluminum isopropoxide is trimeric or tet-rameric. It is therefore conceivable that some hydride transfers will involve Al(OR)3 units that are not coordinated to the carbonyl groups they reduce. These transfers may occur preferentially from the side opposite that exposed to a coordinated Al(OR).3 unit. Such competitive mechanistic pathways might well yield an isomer ratio not in agreement with that produced by less complex reducing agents. 

For efficient action of Y as cocatalysts, it is necessary that in reactions with alkyl halides they behave as bases abstracting proton not as nucleophiles entering undesired nucleophilic substitution. From a variety of possible Y-H, only OH acids—alcohols and phenols, and to smaller extent some NH acids—are shown to be proper cocatalysts. In a model studies of base-induced PTC j8-elimination of HBr from cyclohexyl bromide, it was shown that benzyl and benzhydryl alcohols, 2,2,2-trifluoroethanol, trifluoromethylphenyl carbinol, and mesitol are particularly efficient cocatalysts (71) as shown in equation 159. 

CaoHuO Cyclohexyl-diphenyl-carbinol-methyh ther 6 II 668. 

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