Alkylation of alcohols and related compounds

REACTIONS OF ALKYL HALIDES, ALCOHOLS, AND RELATED COMPOUNDS... 

Guillena G, Ramdn DJ, Yus M (2010) Hydrogen autotransfer in the V-alkylation of amines and related compounds using alcohols and amines as electrophiles. Chem Rev 110(3) 1611-1641... 

The titanium reagents add to aldehydes to give anti vicinal diols. For example, the allenyltitanium reagent generated from 1-alkyl-1-butyne derivatives gives anti 3-alkynic alcohols with high dia-stereoselectivities (Scheme 31). This method has been applied in a stereocontrolled synthesis of ( )-asperlin and related compounds (Scheme 32). °... 

Shape selective catalysis as typically demonstrated by zeolites is of great interest from scientific as well as industrial viewpoint [17], However, the application of zeolites to organic reactions in a liquid-solid system is very limited, because of insufficient acid strength and slow diffusion of reactant molecules in small pores. We reported preliminarily that the microporous Cs salts of H3PW12O40 exhibit shape selectivity in a liquid-solid system [18]. Here we studied in more detail the acidity, micropore structure and catal3rtic activity of the Cs salts and wish to report that the acidic Cs salts exhibit efficient shape selective catalysis toward decomposition of esters, dehydration of alcohol, and alkylation of aromatic compound in liquid-solid system. The results were discussed in relation to the shape selective adsorption and the acidic properties. 

BINOL and related compounds have proved to be effective catalysts for a variety of reactions. Zhang et al.106a and Mori and Nakai106b used an (R)-BINOL-Ti(OPr )4 catalyst system in the enantioselective diethylzinc alkylation of aldehydes, and the corresponding secondary alcohols were obtained with high enantioselectivity. This catalytic system works well even for aliphatic aldehydes. Dialkylzinc addition promoted by TifOPr1 in the presence of (R)- or (A)-BINOL can give excellent results under very mild conditions. Both conversion of the aldehyde and the ee of the product can be over 90% in most cases. The results are summarized in Table 2-14. 

Not only alkenes and arenes but also other types of electron-rich compound can be oxidized by oxygen. Most organometallic reagents react with air, whereby either alkanes are formed by dimerization of the metal-bound alkyl groups (cuprates often react this way [80]) or peroxides or alcohols are formed [81, 82]. The alcohols result from disproportionation or reduction of the peroxides. Similarly, enolates, metalated nitriles, phenolates, enamines, and related compounds with nucleophilic carbon can react with oxygen by intermediate formation of carbon-centered radicals to yield dimers (Section 5.4.6 [83, 84]), peroxides, or alcohols. The oxidation of many organic compounds by air will, therefore, often proceed faster in the presence of bases (Scheme 3.21). 

We have now established sufficient background to consider briefly the kinetics of reactions in water where apolar solutes are involved. For example, if the hydration characteristics of t-butyl alcohol in water are controlled to a marked extent by the hydration of the apolar t-butyl group, then it is likely that the same state of affairs exists for, say t-butyl chloride and other alkyl halides and related compounds in water. In other words, the hydration properties can be characterized by the general statement that, in the solvent co-sphere, water-water interactions > water-solute interactions, but that in the activation process water-solute interaction will increase. Since for apolar solutes, Cp3 > 0, and assuming that in the transition state, Cp3 0, then a tentative prediction is that ACp < 0 and — —Cp3. 

The hydroxy acids are the most important of all the classes of substituted acids. Many of them occur as constituents of plants or animals and they are closely related to other important natural products such as the sugars. They result from the substitution of the hydroxyl groups (—OH), for hydrogen of the alkyl radical in acids. Being mixed alcohol and acid compounds, they possess the properties of both classes of compounds represented and these properties are like as well as different. 

The use of organic halogen compounds as the starting products for the synthesis of other organic chemicals is too immense a field to do more than indicate some of the commercial applications. In his book I4S) on the chemistry of petroleum derivatives, Ellis includes a chapter on the production of alcohols and esters from alkyl halides, and also one on miscellaneous reactions of halo-paraffins and cycloparaffins. The manufacture of amyl alcohols and related products from the chlorides has been well covered 14 ) 1 )-A two-step process for the synthesis of cyclopropane by chlorinating propane from natural gas and dechlorinating with zinc dust was devised in 1936 152). A critical review of syntheses from l,3-dichloro-2-butene was published in Russia in 1950 (1-54). The products obtainable from the allylic chlorides are covered in a number of articles 14If 14 157). 

Peroxides and Related Compounds.— Triphenylphosphine has been shown to react with the dioxetan (61) to give the quinquecovalent compound (62). This decomposes to give an epoxide on heating. Several peroxides and polyperoxides react with alkyl- and aryl-phosphines in the presence of water. Alcohols are... 

Acyloxy- and acylthiopyrazines are convenient acylation reagents for benzylamine, aniline, pyrrolidine, and related compounds (see Section 6.03.8.3). The acylthio compounds are also useful for acylation of alcohols and phenols. Pyrazinyl alkyl sulfoxides (see Section 6.03.8.4) give aldehydes and ketones by treatment with TFAA <91H(32)937>. The pyrazinium chlorochromate salt (181) is formed by addition of chromium(VI) oxide to a solution of pyrazine in hydrochloric acid, and it has proved to be more effective for the oxidation of aliphatic and allyl alcohols to the aldehydes than pcc <83H(20)2029>. 

In the discussion of the chemical properties of alcohols and acids, it was found convenient to consider these compounds as derived from water by the replacement of one hydrogen atom by positive (alkyl) and negative (acyl) radicals, respectively. The relation between the alcohols and inorganic bases, and between the organic and inorganic acids, is shown by the following formulas — ... 

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