Reviews form aliphatic alcohols

Tetrahydrofuranes. Cekovic, BoSnjak, and Mihailovic have reviewed their work on the oxidative cyclization of aliphatic alcohols to tetrahydrofuranes by oxidation with lead tetraacetate. The reagent should be free of acetic acid. Anhydrous calcium carbonate can be added to neutralize the acetic acid in the oxidant and that formed during the reaction. The reaction involves selective oxygenation of a 8-carbon the actual mechanism is uncertain, but is probably a radical reaction. Direct oxidation of the alcohol is generally of minor importance, but P-fragmentation can be a problem, particularly when a stable benzyl or allyl radical is formed. 

RCO2H, R OH, DCC/DMAP, EtjO, 25°C, l-24h, 70-95% yield. This method is suitable for a large variety of hindered and unhindered acids and alcohols. The use of Sc(OTf)3 as a cocatalyst improves the esterification of 3° alcohols. Carboxylic acids that can form ketenes with DCC react preferentially with aliphatic alcohols in the presence of phenols whereas those that do not show the opposite selectivity. In some sterically congested situations the 0-acyl urea will migrate to an unreactive A-acyl urea in competition with esterification. Carbodi-imide I was developed to make the urea by-product water soluble and thus easily washed out. Isoureas are prepared from a carbodiimide and an alcohol which upon reaction with a carboxylic acid give esters in excellent yield. A polymer supported version of this process has been developed. This process has been reviewed. Note that DCC is a potent skin irritant in some individuals. 

The main volatiles in wines are the higher aliphatic alcohols, ethyl esters, and acetates formed from yeasts during fermentation. Acetates are very important flavors characterized by fruity notes, C4-Ci0 fatty acid ethyl esters manly confer fruity scents to the wine. Other wine aroma compounds are C6 alcohols, such as 1-hexanol and cis- and trans-3-hexen-l-ol, 2-phenylethanol, and 2-phenylethyl acetate. Contents of these compounds in wine are linked to the winemaking processes used fermentation temperature, yeast strain type, nitrogen level in must available for yeasts during fermentation, clarification of wine (Rapp and Versini, 1991). Much literature on the wine aroma compounds was reported in reviews by Schreier (1979) and Rapp (1988). 

Aldehydes readily react with alcohols into hemiacetals and acetals. The first reaction involves simple addition, whereas water is liberated in the second reaction. The reactions are acid-catalyzed and reversible. Acid catalysis is, however, not a necessary condition for the reaction to proceed. Frequently, particularly in the case of aliphatic aldehydes, the reaction proceeds without a catalyst. If both alcohol and aldehyde are bifunctional reagents, it is possible that cyclic structures may form or that polymerization may occur. Whether or not one or the other of these reactions occur depends on the energy factors, steric accessibility of the reaction sites, and finally, as in all reversible reactions, on the position of the equilibrium according to the concentration of reagents and products in the solution. Starch, being a polyalcohol, also reacts with aldehydes. This subject was formerly reviewed by Roberts.1274... 

Fatty primary alcohols with similar aliphatic chains to fatty acids tend to occur in the free state in tissues at low concentrations only, but they may be of some metabolic importance as precursors of alkyl lipids, as plant growth regulators and as insect pheromones, for example. In addition, they are found in esterified form in wax esters, which are substantial components of many natural materials. Secondary alcohols may be present in plant surface waxes, together with aliphatic diols which are common constituents of skin lipids. In mammalian tissues, the primary alcohols are saturated or monoenoic, but never di- or polyunsaturated in wax esters of marine origin, the alcohol constituents are often closely related in structure to the fatty acids from which they may derive biosynthetically. The occurrence, chemistry and metabolism of fatty alcohols [577] and their chromatographic properties [577,579] have been reviewed. 

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