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www.clutchprep.com ORGANIC - MCMURRY 9E CH.9 - ALKYNES: AN INTRODUCTION TO ORGANIC SYNTHESIS
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ORGANIC - MCMURRY 9E
CH.9 - ALKYNES: AN INTRODUCTION TO ORGANIC SYNTHESIS
CONCEPT: ALCOHOL NOMENCLATURE
□ Alcohols are named by adding the modifier (-_______) the end of the root.
● Alcohols receive _______________ priority in numbering alkanes
● Locations can be donated _______________ the root “old school” or _______________ the root “new school”
EXAMPLE: Name the following compound:
a.
ORGANIC - MCMURRY 9E
CH.9 - ALKYNES: AN INTRODUCTION TO ORGANIC SYNTHESIS
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CONCEPT: DOUBLE DEHYDROHALOGENATION (ALKYNE SYNTHESIS)
□ When two equivalents of halide are present, bases can eliminate twice, creating alkynes as products
VICINAL: Adjacent to each other (aka “Vicinity”) GEMINAL: On the same carbon (aka “Gemini – Twins”)
EXAMPLE: Supply the mechanism and major/minor products for the following dehydrohalogenation reactions:
a.
b.
ORGANIC - MCMURRY 9E
CH.9 - ALKYNES: AN INTRODUCTION TO ORGANIC SYNTHESIS
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CONCEPT: ALKYNIDE SYNTHESIS
□ Recall that terminal alkynes are uniquely acidic due to the hybridization effect:
● Terminal alkynes can be deprotonated with a strong base
(usually _________ or ___________) to create a strong nucleophiles called
__________________________.
EXAMPLE: Predict the product of the following reaction sequences:
a.
b.
ORGANIC - MCMURRY 9E
CH.9 - ALKYNES: AN INTRODUCTION TO ORGANIC SYNTHESIS
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CONCEPT: HYDROGENATION OF ALKYNES
There are three methods commonly used to saturate double and triple bonds. They differ in the degree of saturation they
provide and in the stereochemistry of their reactions.
Catalytic Hydrogenation or Wilkinson’s Catalyst: Full Saturation
Stereochemistry: Syn Addition
Dissolving Metal Reduction: Partial Saturation
Stereochemistry: Anti Addition
Lindlar’s Catalyst: Partial Saturation
Stereochemistry: Syn Addition
ORGANIC - MCMURRY 9E
CH.9 - ALKYNES: AN INTRODUCTION TO ORGANIC SYNTHESIS
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PRACTICE: Predict the product of the following multi-step synthesis:
ORGANIC - MCMURRY 9E
CH.9 - ALKYNES: AN INTRODUCTION TO ORGANIC SYNTHESIS
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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: __________________________
ORGANIC - MCMURRY 9E
CH.9 - ALKYNES: AN INTRODUCTION TO ORGANIC SYNTHESIS
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CONCEPT: ALKYNE HALOGENATION
Halogenation
□ Product: __________________________
ORGANIC - MCMURRY 9E
CH.9 - ALKYNES: AN INTRODUCTION TO ORGANIC SYNTHESIS
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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: __________________________
ORGANIC - MCMURRY 9E
CH.9 - ALKYNES: AN INTRODUCTION TO ORGANIC SYNTHESIS
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Hydroboration of Alkynes
□ Product: __________________________
ORGANIC - MCMURRY 9E
CH.9 - ALKYNES: AN INTRODUCTION TO ORGANIC SYNTHESIS
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CONCEPT: OXIDATIVE CLEAVAGE
Cleavage of Alkynes: Carboxylic Acid + Carbon Dioxide
EXAMPLE: Predict the product of the following reaction.
ORGANIC - MCMURRY 9E
CH.9 - ALKYNES: AN INTRODUCTION TO ORGANIC SYNTHESIS
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CONCEPT: OXIDATION
□ Oxidizing agents are used to oxidize molecules
● Most oxidizing agents add as much oxygen as possible while not breaking ANY C-C bonds.
EXAMPLE: Which of the following compounds could be oxidized?
□ These are called strong oxidizing agents. They include KMnO4 and the Cr6+ reagents (H2Cr2O4, CrO3, K2Cr2O7, etc.)
EXAMPLE: Draw the products of the previous molecules with a strong oxidizing agent
□ PCC is a weak oxidizing agent. It reacts similar but can only add ____ equivalent of oxygen to 1º alcohols.
ORGANIC - MCMURRY 9E
CH.9 - ALKYNES: AN INTRODUCTION TO ORGANIC SYNTHESIS
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PRACTICE: Provide the major product for the following oxidation reaction.
CH3
CH3 CH3
OHOH
OH PCC
CH2Cl2
PRACTICE: Provide the major product for the following oxidation reaction.
CH3CH2 1. O3
2. Zn, CH3CO2H
PRACTICE: Provide the major product for the following oxidation reaction.
KMnO4
H+
OH
OH
OH
PRACTICE: Provide the major product for the following oxidation reaction.
ORGANIC - MCMURRY 9E
CH.9 - ALKYNES: AN INTRODUCTION TO ORGANIC SYNTHESIS
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PRACTICE: Determine the major product for the following reaction.
PRACTICE: Determine the major product for the following reaction.
PRACTICE: Provide the necessary reagents for the following transformation.
ORGANIC - MCMURRY 9E
CH.9 - ALKYNES: AN INTRODUCTION TO ORGANIC SYNTHESIS
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CONCEPT: OXIDATIVE CLEAVAGE
Strong Oxidative Cleavage: Ketones + Carboxylic Acid + Carbon Dioxide
PRACTICE: Predict the product of the following reaction.
ORGANIC - MCMURRY 9E
CH.9 - ALKYNES: AN INTRODUCTION TO ORGANIC SYNTHESIS
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CONCEPT: MULTISTEP SYNTHESIS
Predict the MAJOR products of the following multistep transformations.
a.
b.
ORGANIC - MCMURRY 9E
CH.9 - ALKYNES: AN INTRODUCTION TO ORGANIC SYNTHESIS
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CONCEPT: RETROSYNTHESIS
Provide the reagents to best perform the following transformations.
a.
b.
ORGANIC - MCMURRY 9E
CH.9 - ALKYNES: AN INTRODUCTION TO ORGANIC SYNTHESIS
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