Alcohols, Enols, and Phenols

For all of these related compounds (alcohols, enols, phenols, ethers, thiols, and thioethers), some properties of which are provided in Table 8.3, it might also be anticipated that the nonbonding electrons (Chapter 1) on oxygen or sulfur could participate in reactions occurring elsewhere in the organic framework, and, indeed, it is common to find that processes taking place remote to the heteroatom are also affected by its presence. 

Finally, the higher oxidation states of sulfur (Chapter 5) are also important. The brief treatment here is supplemented by materials that will be developed as parts of other chapters. 

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Hydrogenolysis of the carbon-oxygen bond in alcohols, enols and phenols is relatively difficult, regardless of type. 

Part I. The Reactions of Alcohols, Enols, and Phenols Oxidation, Reduction, Substitution, Addition, Elimination, and Rearrangement Part II. Ethers... 

PART I. ALCOHOLS, ENOLS, AND PHENOLS A. ACIDITY AND BASICITY... 

Current ideas about acids and bases as applied to alcohols, enols, and phenols, as noted earlier (Chapter 5), are divided into the main categories of proton donors/ acceptors (Brpnsted acids/bases) and electron acceptors/donors (Lewis acids/bases). Because alcohols, enols, and phenols all bear protons on oxygen, which can be donated and have sufficient electron density on oxygen to permit protonation, they readily fit the Brpnsted criteria. Flowever, since the electron density on oxygen can also be donated to nonprotonaceous species (e.g., the empty orbital on BFj [Chapter 1]), alcohols, enols, and phenols also qualify as Lewis bases. 

The first problem is the nature of the leaving group. If the leaving group, in the case of alcohols, enols, and phenols, is to be the hydroxyl (-OH), it will leave as hydroxide (OH ) anion and that ion is the conjugate base of the weak acid water (H-OH). Hydroxide (OH ) is a poor leaving group. 

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