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CONCEPT: GENERAL MECHANISM Addition reactions are ones in which 1 bond is broken and 2 new bonds are formed. They are the inverse of reactions EXAMPLE: Provide the mechanism for the following addition reaction. Page 2
CONCEPT: MARKOVNIKOV S RULE When we try to perform addition on asymmetric double bonds, we now get two possible products. Markovnikov s Rule predicts that the carbocation will ALWAYS form on the carbon EXAMPLE: Provide the mechanism for the following addition reaction. Page 3
CONCEPT: HYDROHALOGENATION General Reaction: EXAMPLE: Provide the mechanism for the following addition reaction. Page 4
CONCEPT: ACID-CATALYZED HYDRATION Same reagents as acid-catalyzed dehydration, except starting with a instead of an alcohol. Same as the general mechanism hydrohalogenation, except with as the nucleophile Remember that EVERY acid-cat. mechanism begins with and ends with General Reaction: EXAMPLE: Provide the mechanism for the following addition reaction. Page 5
PRACTICE: Provide the mechanism and predict the product of the following reaction. Page 6
CONCEPT: OXYMERCURATION-REDUCTION General Reaction: Mechanism: 1. Electrophilic Addition 2. Nucleophilic Substitution (SN 2 ) 3. Reduction (demurcuration) Page 7
PRACTICE: Provide the mechanism and predict the product of the following reactions. a. Page 8
CONCEPT: HYDROBORATION-OXIDATION General Reaction: Mechanism: 1. Electrophilic Addition 2. Oxidation Page 9
PRACTICE: Provide the mechanism and predict the product of the following reactions. a. b. Page 10
CONCEPT: CATALYTIC HYDROGENATION AND WILKINSON S CATALYST General Reaction: PRACTICE: Provide the products for the following reaction. Page 11
CONCEPT: HALOGENATION General Reaction: Mechanism: 1. Electrophilic Addition 2. Nucleophilic Substitution (SN 2 ) Page 12
CONCEPT: HALOHYDRIN FORMATION General Reaction: Mechanism: 1. Electrophilic Addition 2. Nucleophilic Substitution (SN 2 ) Page 13
PRACTICE: Provide the mechanism and predict the product of the following reactions. a. b. Page 14
CONCEPT: CYCLOPROPANATION Carbenes are reactive intermediates. They are unstable because they violate the. There are 4 methods commonly used to introduce carbene intermediates: 1. 2. 3. 4. Page 15
CONCEPT: EPOXIDATION Epoxides are added to double bonds using Common reagents are and Mechanism: Epoxides can also be generated though an intramolecular reaction of halohydrins. Mechanism: Page 16
CONCEPT: EPOXIDE RING OPENING 1. Acid-Catalyzed Ring Opening Following protonation of the epoxide, the nucleophile will attack the side of the ring with the most character: 2. Base-Catalyzed Ring Opening The strong nucleophile will attack the side of the ring that is substituted Page 17
CONCEPT: SYN VICINAL DIHYDROXYLATION General Reaction: EXAMPLE: Predict the product for the following multi-step reaction. Page 18
CONCEPT: WEAK OXIDATIVE CLEAVAGE Ozonolysis: Ketones + Aldehydes + Formaldehyde PRACTICE: Predict the products of the following reaction Page 19
CONCEPT: OXIDATIVE CLEAVAGE Strong Oxidative Cleavage: Ketones + Carboxylic Acid + Carbon Dioxide PRACTICE: Predict the product of the following reaction. Page 20
CONCEPT: OXIDATIVE CLEAVAGE Cleavage of Alkynes: Carboxylic Acid + Carbon Dioxide EXAMPLE: Predict the product of the following reaction. Page 21
CONCEPT: ALKYNE HYDROHALOGENATION Alkynes react with some addition reagents in excess to produce double addition products. Keep in mind that carbocations CANNOT easily rearrange. Hydrohalogenation of Alkynes Product: Page 22
CONCEPT: ALKYNE HALOGENATION Halogenation Product: Page 23
CONCEPT: ALKYNE HYDRATION Vinyl alcohols are uniquely reactive due to a phenomenon called tautomerization. They reversibly swap the positions of a and a bond. Oxymercuration of Alkynes Product: Page 24
Hydroboration of Alkynes Product: Page 25