TOPIC 10. ALCOHOLS AND ETHERS (chapter 11)

OBJECTIVES 1. Name and describe structure of alcohols and ethers. 2. Describe mechanisms of reactions of alcohols and ethers. 3. Predict the product(s) of reactions of alcohols and ethers. 4. Provide syntheses of alcohols and ethers.

EXAMPLES, STRUCTURE, NOMENCLATURE & PHYSICAL PROPERTIES Prob:11.31-32 Alcohols: Nomenclature Trivial names

Ethers: Nomenclature

Physical Properties Alcohols have higher boiling points than ethers with same formula Boiling point increases with molecular weight Et2O: volatile, flammable, anesthetic; oxidizes slowly in air to give explosive peroxide. tBuOMe (MTBE): controversial oxygenated fuel additive http://home.vicnet.net.au/~einstein/stories1999/medicine.htm

SYNTHESIS OF ALCOHOLS Review: Acid Catalyzed Hydration of Alkenes S1.4-7 Prob:11.33, 35(c-e),40,46 Review: Acid Catalyzed Hydration of Alkenes Intermediate carbocations can rearrange.

Oxymercuration-Demercuration of alkenes e.g., Step 1: Oxymercuration Step 2: Demercuration

Mechanism

Hydroboration-Oxidation of Alkenes: Anti-Markovnikov Hydration of Alkenes e.g., Step 1: Hydroboration Step 2: Oxidation

Mechanism: Regiochemistry

Stereochemistry

ALCOHOLS AS ACIDS AND BASES Alcohols are weak acids and weak bases. However, acid-base chemistry is important in activating the electrophilic and nucleophilic character of alcohols, respectively.

MESYLATES AND TOSYLATES IN SN2 REACTIONS R’ = Me: mesylate (Ms) 4-methylphenyl: tosylate (Ts)

CONVERSION OF ALCOHOLS TO ALKYL HALIDES Alcohol + H-Hal 3o Alcohols: SN1

1o Alcohols: SN2

Other reagents

SYNTHESIS AND REACTIONS OF ETHERS S1.15-18 Prob:11.38 Dehydration of Alcohols

Acid Catalyzed Hydrolysis of Ethers

Williamson Ether Synthesis

Designing Williamson Ether Syntheses You could suggest making either C-O bond of the ether.

EPOXIDES S1.16,18 Prob 11.38 Synthesis MMPP mCPBA

Nucleophilic Ring-opening of Epoxides Stereochemistry

Regiochemistry

MULTISTEP SYNTHESES Prob 11.36,42, 44,45,47 Problem: Propose a synthesis of 1-methyl-1,2-cyclopenanediol (with the two hydroxy groups trans to one another) from methylcyclopentane.

Problem: An insect physiologist required hex-4Z-en-3-ol for the study of insect pheromones. Propose a synthesis of hex-4Z-en-3-ol from pentene

CHAPTER 11 ON FINAL Types of Questions Preparing for Final - Describe mechanisms of reactions involving alcohols and ethers - Predict the products of reactions involving alcohols and ethers - Propose syntheses of alcohols and ethers The problems in the book are good examples of the types of problems on the exam. Preparing for Final - Work as many problems as possible. - Work in groups. - Do the “Learning Group Problem” at the end of the chapter.

THE LONG AND WINDING ROAD….. Where we have been: Description of the Structure of Organic Molecules Description of reaction pathways Substitution at sp3 carbons bearing leaving groups Elimination from sp3 carbons bearing leaving groups Addition to alkenes and alkynes Development of multistep (2-3 step) Synthetic Pathways Determination of Structure

…..GOES ON FOREVER Where we are going… CHEM 2312: Organic Chemistry – 2 Preparing compounds with an impact on human health and nutrition, the economy, and your well-being. Particular emphasis on the chemistry of benzene rings, carbonyl-containing functional groups, C-C bond formation to prepare complex (useful!) organic molecules, sex, drugs, and rock and roll.

That's All, Folks