【正文】 Chapt 11 Alcohols and Ethers ?醇、醚的命名 ?醇的制備 ——羥汞化－還原反應(yīng) ——硼氫化－氧化反應(yīng) ?醇的化學(xué)反應(yīng) ?醚的制備 ?醚的化學(xué)反應(yīng) ——保護基 ?環(huán)氧化合物 Structure and Nomencalture ? Alcohols: OH is attached to a saturated carbon atom. ? Enols: OH is attached to an unsaturated carbon atom. C H 2 O HCH3CH2OH Ethanol H–C≡CCH2OH 2Propynol CH2=CHCH2OH 2Propenol Benzyl alcohol ? Phenols: OH is attached to a benzene ring. ? Ethers are pounds whose molecules have an oxygen atom bonded to two carbon atom. O H O HH 3 CPhenol pMethylphenol (pCresol) CH2=CHCH2–O–CH3 Allyl methyl ether 烯丙基 Nomenclature of Ethers ? IUPAC substitutive names are used for more plicated ethers and for pounds with more than one ether linkage. ? Ethers are named as alkoxyalkanes, alkoxyalkenes, and alkoxyarenes. ? Simple ethers are frequently given mon radicofunctional names. Methyl phenyl ether (Anisole茴香醚 ， 苯甲醚 ) O C H 31,2Dimethoxyethane C H 3 C H C H 2 C H 2 C H 3O C H 3O C H 2 C H 3H 3 C CH3–O–CH2CH2–O–CH3 2Methoxypentane 1Ethoxy4methylbenzene ? Cyclic ethers can be names in several ways. ? Replacement nomenclature: relating the cyclic ether to the corresponding hydrocarbon ring system and use the prefix oxa to indicate that an oxygen atom replaces a CH2 group. ? Oxirane: a cyclic threemembered ether (epoxide). ? Oxetane: a cyclic fourmembered ether. ? Common names: given in parentheses. Oxacyclopropane or oxirane (ethylene oxide) O O OOO1,4Dioxacyclohexane (1,4dioxane) Oxacyclobutane or oxetane Oxacyclopentane (tertahydrofuran) Physical Properties of Alcohols ? Alcohols have much higher . than parable ethers or hydrocarbons. Hbond OH 3 CHH OC H 3OC H 3H? Methanol, ethanol, both propanols, and tertbutyl alcohol are pletely miscible with water. ? 95%ethanol and 5%water ? azeotrope(共沸物 ,176。 C) ? The solubility of alcohols in water gradually decreases as the hydrocarbon portion of the molecule lengthens. Physical Properties Ethers ? Ethers have similar boiling points that are parable with those of hydrocarbons of the same molecular weight. The . of diethyl ether (MW = 74) is 。 that of pentane (MW = 74) is 36 0C. ? Ethers are able to form hydrogen bonds with pounds such as water. ? Ethers have solubilities in water that are similar to those of alcohols of the same molecular weight. Diethyl ether and 1butanol have the same solubility in water, approximately 8g/100 mL at room temperature. Pentane, by contrast, is virtually insoluble in water. Synthesis of Alcohols from Alkenes ? AcidCatalyzed Hydration of Alkenes: C C H A CHC+ H 2 O? H 2 OC CH OH HC CH OHH A+ + +A l k e n e A l c o h o lA ?+++ A ?Markovnikov’s rule。 limited usefulness(rearrangements ) ? OxymercurationDemercuration:Markovnikov addition of H– and –OH ? HydroborationOxidation: antiMarkovnikov but syn addition of H– and –OH Alcohols from Alkenes through OxymercurationDemercuration Complete within 20 s to 10 min at rt or below Step 1: Oxymercuration（ 羥汞化 ） C C H 2 O T H F C CH gO H O C C H 3H g O C C H 3OC H 3 C O HO+ + +2 OStep 2: Demercuration（ 脫汞 ） O H ? + N a B H 4 C CO H H+ H g + C H 3 C O ?O+C CH gO H O C C H 3Oless than an hour High yields, usually greater than 90% ? Oxymercurationdemercuration is highly regioselective. CC H 3CH O C H 3CH O C H 31 M e t h y l c y c l o p e n t e n e1 M e t h y l c y c l o p e n t a n o lH g O A c HH g ( O A c ) 2T H F H 2 ON a B H 4O H ?( 6 m i n )+ H g( 2 0 s ) H H? Rearrangements of the carbon skeleton seldom occur in oxymercuration demercuration. 1 . H g ( O A c ) 2 / T H F H 2 O2 . N a B H 4 , O H ?C H 3 C C H C H 2 C H 3 C C HO HC H 3C H 3 C H 3C H 33 , 3 D i m e t h y l 1 b u t e n e 3 , 3 D i m e t h y l 2 b u t a n o l( 9 4 % )CHHHSolvomercurationdemercuration: N a B H 4 , O H ?C C C CO RH g O 2 C C F 3C CO RHA l k e n e ( A l k o x y a l k y l ) m e r c u r i c t r i f l u o r o a c e t a t eH g ( O 2 C C F 3 ) 2 / T H F R O Hs o l v o m e r c u r a t i o nE t h e rd e m e r c u r a t i o nHydroboration（ 硼氫化反應(yīng)） : ? Carried out by using the boro