Alcohols with metals

The oxidation of alcohols with metal dichromates, other than sodium or potassium dichromate, has been little explored. Hydrated zinc dichromate (ZnCr207 3H20)367 368a and ferric dichromate [Fe2(Cr207)3],368b—which are very easy to prepare as stable solids—are able to oxidize alcohols in organic solvents.368 Zinc dichromate is particularly efficient in the transformation of a-hydroxyphosphonates into a-ketophosphonates.369... 

Summary 99% ethyl alcohol is obtained by treating 95% ethyl alcohol with metallic sodium. The metallic sodium reacts with the water in the binary azeotrope, freeing the alcohol. Once the water has been neutralized (forming sodium hydroxide and sodium ethoxide), the mixture is distilled to recover the anhydrous ethyl alcohol. 

Compared to the multistep electron-transfer process shown in Scheme 3.4, more simple aerobic oxidations of alcohols were reported with various homogeneous and heterogeneous ruthenium catalysts. The aerobic oxidation of alcohols with metal catalysts is an attractive method for economical and environmental reasons. Aerobic oxidation of alcohols can be carried out using RUCI3 catalyst with moderate conversion and selectivities (Eq. 3.13) [31]. Since this reaction was first reported, an arduous search for suitable catalysts has been continuing using various ruthenium complexes (Table 3.1). 

It has been known for some time that NCAs of racemic a-amino acids can be converted to optically active poly a-amino acids with the aid of optically active alcohols or combinations of such alcohols with metal alkyls as initiators. Such processes have been termed asymmetric-selective or stereo-selective . Some of these investigations will be described subsequently. Biihrer and Elias [63] have recently made a comprehensive investigation of the kinetics of polymerization of DL-leucine NCA initiated by a series of optically active primary and... 

For certain special purposes (Secs. 26.2 and 26.3) even the slight trace of water found in commercial absolute alcohol must be removed. This can be accomplished by treatment of the alcohol with metallic magnesium water is converted into insoluble Mg(OH)2, from which the alcohol is then distilled. 

Derivation (1) Oxidation of cumene (2) dehydrogenation or oxidation of isopropyl alcohol with metallic catalyst (3) vapor-phase oxidation of butane (4) by-product of synthetic glycerol production. 

Most acyclic ethers can be prepared using Williamson synthesis. This involves reacting an alkoxide with a haloalkane. As stated previously, alkoxides are created by reacting an alcohol with metallic sodium or potassium. 

Epoxidalion of 2-mediyl 4iulm-2<)l, la, and of other tertiaiy alylic alcohols with metal alooidellar taityl hydroperoaide oombmalions. A conqnrison with pennetic aod. 

Alkyl hypochlorites and hypobromites are relatively stable molecules alkyl hypoiodites can only be prepared in situ, usually by the reaction of alcohols with metal acetates or oxides and iodine or by the reaction of alcohols with a hypervalent iodine compound and iodine.1319 Alkyl hypochlorites and hypoiodites can be utilized in reactions that parallel those of the organic nitrites (Barton reaction Section 6.4.2). For example, the photochemistry of the steroidal hypoiodite 497, prepared by the reaction of the corresponding alcohol with iodine oxide (I2O) generated from mercury(II) oxide and molecular iodine in situ, affords a new five-membered ring via an O I bond fission, 1,5-hydrogen abstraction and substitution (Scheme 6.244).1353... 

In contrast to the considerable amount of successful attention devoted to the asymmetric reduction of prostereogenic ketones to chiral alcohols with metal hydride reagents (see Section D.2.3 and ref 1), corresponding studies and identification of useful stereoselective conversions of stereo-genic imine derivatives to amines have been sparse, and only limited success has been obtained. 

A glance at the literature provided other examples of homogeneous reactions of water or alcohols with metal carbonyls which are presumably promoted by surfaces we thus decided to write a short review on the subject. This task was hard for several reasons. 

S.4.3 Reactions of propargyl alcohols with metal carbonyl clusters of the iron triad... 

The examples discussed above indicate that although - at present - several homogeneous and surface-mediated reactions of water or alcohols with metal carbonyl clusters are known, much more work is still needed to gain a full knowledge of these reactions and for exploiting this reactivity for synthetic or catalytic purposes. 

LOX). The second line shows the conversion of the hydroperoxide to an epoxy alcohol with metal ion catalysts and the enzyme epoxygenase. 

Reactions of alcohols with metals yield special salts called alcoholates or alkox-ides. For example, methanol reacts with sodium producing sodium methanolate (sodium methoxide) with the evolution of hydrogen ... 

Alcoholates (alkoxides), which were already mentioned in the discussion on the reactions of alcohols with metals, behave as strong bases and are good nucleophiles. In the middle of nineteenth century Alexander William Williamson succeeded in preparing ethers in the reactions of alkoxides with primary alkyl halides. Later it was demonsttated that these reactions follow the Sn2 mechanism. 

Several common synthetic strategies for the formation of transition metal-heteroatom bonds can be used for the preparation of early transition metal alkoxides, as shown in Equation 4.57. These methods include (1) metathesis between metal halides and alkali metal salts of the corresponding alcohols (2) direct reaction of the alcohols with metal halides in the presence of a base and (3) protonolysis of metal alkyls, amides, or alkoxides with more acidic alcohols. 

In chemistry related to the reactions of alkali metal alkoxides with late metal halide complexes, late metal alkoxides have been formed by the reaction of alcohols with metal halides in the presence of a base. This process has been used to form arylpalladium alkoxides during the coupling of aryl halides with alcohols discussed in Chapter 19 (cross-coupling). In addition, Milstein used an intramolecular version of this process to prepare the metallaoxetane in Equation 4.68. ... 

The alkali-metal derivatives of perfluoro-t-butyl alcohol, (CF3)sC OM (M = Li, Na, or K), best prepared by reaction of the alcohol with metal hydride in anhydrous ether, have been shown to resist thermal decomposition [for example, the sodium alkoxide can be melted (143 °Q and distilled (232°C) with no apparent change in composition] the same is true of the alkoxides CF3aC(CF3)3-ONa, Ca,-C(CF8)2-ONa, and (CF3)2CHOM (M = Li or Na), which likewise possess no a-fluorine substituent [cf. 

The oxidation of alcohols with metal ions in aqueous solutions was studied in detail. Alcohol enters into the inner coordination sphere of the oxidation where the electron transfer from the alcohol to the ion occurs... 

Although alkyl hypochlorites and hypobromites are isolable species, alkyl hypoiodites are not isolable. They can only be prepared in situ, either by the reaction of alcohols with metal acetates or oxide and iodine in solution, or by the reaction of alcohols with a hypervalent iodine compound and iodine in... 

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