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8 Hydroxy Functional Group: Alcohols: Properties, Preparation, and Strategy of Synthesis With this chapter we begin a detailed examination of alcohols, molecules containing the hydroxy functional group. Apart from carbonyl compounds, alcohols are the most important molecules in organic chemistry. They can be prepared from many different types of compounds, and, in turn, they can be converted into many dif- ferent types of compounds. They therefore play a central role in organic chemistry. Moreover, their prepara- tions, properties, and reactions serve as excellent illustrations of the logic underlying the behavior of organic compounds. The approach to Chapters 8 and 9 is similar to that used in Chapters 6 and 7. However-and this is very important-alcohols have much more potential for chemical conversion than haloalkanes do. You must be pre- pared even more than before to focus on the functional groups and their polar bonds as sites of possible reac- tivity. A comparison of, first, the bonds and, second, the potential bonding changes available in alcohols and haloalkanes is useful. Haloalkane chemistry involves mainly three bonds: 3 H 1 C C X 2 Substitution Elimination H C C Y C C Substitution breaks bond 3. Elimination breaks bonds and 3, and "doubles" bond 2. By comparison, five bonds may participate in chemical reactions of alcohols: H H I 5 C C O 4 H 2 3 We focus first on properties of alcohols. Then we examine their preparation, using this discussion to exam- ine the general problem of synthetic strategy: how to logically plan a practical and efficient sequence of chem- ical steps that allows the conversion of a starting material into an organic product. 146