大二有机第八章

1、Review1. The formation of Hydrogen bondingGood leaving group2. Good nucleophile3. Dehydration reaction(1) Intramolecular dehydration of alcohols to yield AlkeneE1， C+ rearrangement， Saytzeff s rule- 2ROH ，3ROH(2) Intermolecular dehydration of alcohols to yield ether(醚)SN2, to synthesis symmetric eth

2、ers - 1ROH, ReviewExercise:1. How to explain the change trend of the boiling point?The formation of hydrogen bondsReview2. Propose a mechanism of the following reactions:Solution:Chemical Properties of Alcohols(3) Dehydration of 1,2-Diol to yield ketone (Pinacol rearrangement)频哪醇重排Octet rule 八隅体规则 ？

3、P330 中文Pinacol rearrangementChemical Properties of AlcoholsExercise：Propose a mechanism for the following reaction:3. Conversion of Alcohols into Alkyl HalidesChemical Properties of Alcohols Alcohols can react with Lucas reagent (ZnCl2/HCl), different kinds of alcohols have different reactivity.Reac

4、t at onceReact after a momentReact after heating(1) React with Lucas reagentThe phenomenon of this reaction is: the solution turns turbid (浑浊)P324-327 中文Chemical Properties of Alcohols Lucas reagent can be used to differentiate different kind of alcohols, the relative reactivity is:benzyl alcohol Al

5、lyl alcohol 3o ROH 2o ROH 1o ROHMechanism:Allyl alcohol，benzyl alcohol， 3o ROH and 2o ROH -SN1; 1o ROH -SN2Nucleophilic Substitution reaction：Chemical Properties of AlcoholsThe relative reactivity of HX is: HI HBr HClExercise: Order the relative reactivity of the following compounds towards Lucas re

6、agent: a. 2- Butanol b. 2-methyl-2-butanol c. 2-methyl-1- propanol （ b a c ）Chemical Properties of AlcoholsPropose a mechanism of the following reaction:(2) React with phosphorus halides (卤化磷) Chemical Properties of AlcoholsThe unsaturated bonds reserved No arrangementThe characteristics of this rea

7、ction:机理不做要求!Chemical Properties of Alcohols(3) React with thionyl chloride (亚硫酰氯) pyridineEasy separation of the product;No arrangement;c. Retention of configuration(构型保持)The characteristics of this reaction:机理不做要求!Chemical Properties of AlcoholsExercise：(1) +HX, SN1, C+ rearrangement (2) +PX3, no

8、rearrangement (3) +SOCl2, no arrangement, retention of configurationChemical Properties of Alcohols4. Esters (酯) formationMonomethyl sulfateDimethyl sulfate(CH3)2SO4 is a good methylation (甲基化) reagent(1) React with inorganic acidP321-323 中文甘油三硝酸酯glyceryl trinitrate遇到震动会发生强烈爆炸，为了使用时安全通常将其与一些惰性的材料混合。

9、诺贝尔(Nobel)将硝化甘油与木粉、硝石和碳酸钙混制而发明一种炸药代纳迈(Dynamite) 这是一种在临床上可用做缓解心绞痛的药物(硝酸甘油)Chemical Properties of AlcoholsChemical Properties of Alcohols(2) React with organic acids and their derivatives(衍生物) Low yield!p-Toluene sulfonic acid TosOH, 对甲苯磺酸Tosylate对甲苯磺酸酯How to improve the isolate yield?Reversible!对甲苯磺酰

10、基 Tosyl T CH3SO2os=CH3SO2Chemical Properties of Alcohols Alcohols react with p-toluenesulfonyl chloride(对甲苯磺酰氯) (p-TosCl) in pyridine solution to yield alkyl tosylates.p-Toluenesulfonyl chloride TosCl 对甲苯磺酰氯OTosOTos is a good leaving group and applied widely in organic synthesisChemical Properties o

11、f AlcoholsExercise: The tosylate of (2R, 3S)-3-phenyl-2-butanol undergoes E2 elimination on treatment with sodium ethoxide to yield (Z)-2-phenyl-2-butene. Explain, using Newman projections.E2Chemical Properties of Alcohols5. Ethers (醚) formationWilliamson ether synthesis-for unsymmetrical ethersabab

12、Unsymmetrical ethers are best prepared by reaction of more hindered alkoxide with the less hindered alkyl halideP257-258Exercise: How to synthesis the following compound with organic materials (less than four carbons )Chemical Properties of Alcohols6. Oxidation of AlcoholsChemical Properties of Alco

13、hols One of the most valuable reactions of alcohols is their oxidation to yield carbonyl compounds (羰基化合物)-the opposite of the reduction of a carbonyl compound to yield an alcohol.Primary alcoholsSecondary alcoholsTertiary alcoholsP225(英), P331-334 中文Chemical Properties of Alcohols The oxidation of

14、a primary or secondary alcohol can be plished by any of a large number of reagents, including KMnO4, Na2Cr2O7 and CrO3. Chemical Properties of Alcohols One of the best methods for preparing an aldehyde from a primary alcohol on a laboratory scale is to use pyridinium chlorochromate (PCC) in dichloro

15、methane solvent.Chemical Properties of Alcohols7. Oxidation of - diolperiodic acid高碘酸This reaction can be used to differentiate the - diollead tetraacetate四乙酸铅lead acetate乙酸铅2Chemical Properties of Alcohols3 An diol undergoes reaction with HIO4, yields the following compound, propose the structure o

16、f the diol.Chemical Properties of AlcoholsExercise: (1) (2) Nomenclature of Alcohols and PhenolsChemical Properties of AlcoholsDefinition and Classification of Alcohols and Phenols Preparation of Alcohols and PhenolsChemical Properties of Phenols.Chapter Eight Alcohols and Phenolsp-conjugated effect

17、Chemical Properties of Phenols1. Phenol has stronger acidity than alcohol.2. Strengthen the C-O bond, making the substitution and elimination reactions are difficult to occur. 3. OH actives the benzene ring. Phenol Chemical Properties of Phenols1. The acidity of PhenolspKa Ethanol = 15.9H2O = 15.0Ph

18、enol = 10.0p-conjugated effect stabilizes the phenoxy anionP249-250(英), (1) To distinguish and separate phenols from most alcoholssodium phenolate, water-solubleChemical Properties of Phenolsphenols dissolve in aqueous sodium hydroxide, whereas most alcohols with six carbon atoms or more do not, giv

19、e us a convenient means for distinguishing and separating phenols from most alcohols.pKa = 18pKa = 9.89No reaction Chemical Properties of Phenols(2) To distinguish and separate phenols from carboxylic acidspKa: H2CO3 = 6.38Phenol = 10.0 Most phenol are not soluble in aqueous sodium bicarbonate (NaHC

20、O3), but carboxylic acids are soluble, Thus, provides a method for distinguishing and separating most phenols from carboxylic acids.No reaction sodium carboxylate, water-solubleChemical Properties of Phenols(3) The acidity of substituted phenols:Relative acidity: Relative stability:12345Chemical Pro

21、perties of PhenolsComparing the relative acidity of the following compounds:Exercise:苦味酸 pKa 1Chemical Properties of Phenols2. The formation of etherphenolic etherP259 (英) 3. The formation of esterChemical Properties of Phenolsphenolic ester酚酯P336-337 中文4. The arrangement of phenolic esterChemical Properties of PhenolsFries arrangementphenolic ketone酚酮5. The oxidation of phenolsChemical Properties of Phenolspara-benzoquinone6. The color reaction with FeCl3All the enols(