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CHEM 125B - Freshman Organic Chemistry II

Lecture 26 - Aromatic Substitution in Synthesis: Friedel-Crafts and Moses Gomberg. The Friedel-Crafts reaction creates new alkyl- or acyl-aromatic bonds, with or without cation rearrangement. Designing reaction sequences, especially those involving diazonium intermediates, so as to access a wide variety of substituted benzenes provides a good introduction to the challenges of synthetic organic chemistry. Aromatic rings with strong electron withdrawal can undergo nucleophilic aromatic substitution, which plays an important role in biochemistry. The special properties of phenyl-substituted alkanes, especially benzylic reactivity and steric hindrance, played an important role in the development of organic chemistry a century ago. (from oyc.yale.edu)

Lecture 26 - Aromatic Substitution in Synthesis: Friedel-Crafts and Moses Gomberg

Time Lecture Chapters
[00:00:00] 1. Discovery of Friedel-Crafts Alkylation and Acylation
[00:13:26] 2. Avoiding Friedel-Crafts Rearrangements
[00:19:48] 3. Synthetic Accessibility via Aromatic Substitution; Diazonium Salts
[00:35:15] 4. Nucleophilic Aromatic Substitution and NADH Reduction
[00:40:44] 5. Benzylic Reactivity, Steric Hindrance, and Moses Gomberg

References
Lecture 26 - Aromatic Substitution in Synthesis: Friedel-Crafts and Moses Gomberg
Instructor: Professor J. Michael McBride. Resources: Professor McBride's website resource for CHEM 125b (Spring 2011). Transcript [html]. Audio [mp3]. Download Video [mov].

Go to the Course Home or watch other lectures:

Lecture 01 - Mechanism: How Energies and Kinetic Order Influence Reaction Rates
Lecture 02 - Peculiar Rate Laws, Bond Dissociation Energies, and Relative Reactivities
Lecture 03 - Rate and Selectivity in Radical-Chain Reactions
Lecture 04 - Electronegativity, Bond Strength, Electrostatics, and Non-Bonded Interactions
Lecture 05 - Solvation, H-Bonding, and Ionophores
Lecture 06 - Bronsted Acidity and the Generality of Nucleophilic Substitution
Lecture 07 - Nucleophilic Substitution Tools - Stereochemistry, Rate Law, Substrate, Nucleophile, Leaving Group
Lecture 08 - Solvent, Leaving Group, Bridgehead Substitution, and Pentavalent Carbon
Lecture 09 - Pentavalent Carbon? E2, SN1, E1
Lecture 10 - Cation Intermediates - Alkenes: Formation, Addition, and Stability
Lecture 11 - Carbocations and the Mechanism of Electrophilic Addition to Alkenes and Alkynes
Lecture 12 - Nucleophilic Participation During Electrophilic Addition to Alkenes
Lecture 13 - Addition to Form Three-Membered Rings: Carbenoids and Epoxidation
Lecture 14 - Epoxide Opening, Dipolar Cycloaddition, and Ozonolysis
Lecture 15 - Metals and Catalysis in Alkene Oxidation, Hydrogenation, Metathesis, and Polymerization
Lecture 16 - Isoprenoids, Rubber, and Tuning Polymer Properties
Lecture 17 - Alkynes; Conjugation in Allylic Intermediates and Dienes
Lecture 18 - Linear and Cyclic Conjugation Theory; 4n+2 Aromaticity
Lecture 19 - Aromatic Transition States: Cycloaddition and Electrocyclic Reactions
Lecture 20 - Electronic and Vibrational Spectroscopy
Lecture 21 - Functional Groups and Fingerprints in IR Spectroscopy; Precession of Magnetic Nuclei
Lecture 22 - Medical MRI and Chemical NMR
Lecture 23 - Diamagnetic Anisotropy and Spin-Spin Splitting
Lecture 24 - Higher-Order Effects, Dynamics, and the NMR Time Scale
Lecture 25 - C-13 and 2D NMR - Electrophilic Aromatic Substitution
Lecture 26 - Aromatic Substitution in Synthesis: Friedel-Crafts and Moses Gomberg
Lecture 27 - Triphenylmethyl and an Introduction to Carbonyl Chemistry
Lecture 28 - Mechanism and Equilibrium of Carbonyl Reactions
Lecture 29 - Imines and Enamines; Oxidation and Reduction
Lecture 30 - Oxidation States and Mechanisms
Lecture 31 - Periodate Cleavage, Retrosynthesis, and Green Chemistry
Lecture 32 - Measuring Bond Energies: Guest Lecture by Prof. G. Barney Ellison
Lecture 33 - Green Chemistry; Acids and Acid Derivatives
Lecture 34 - Acids and Acid Derivatives
Lecture 35 - Acyl Insertions and alpha-Reactivity
Lecture 36 - alpha-Reactivity and Condensation Reactions
Lecture 37 - Proving the Configuration of Glucose and Synthesizing Two Unnatural Products
Lecture 38 - Review: Synthesis of Cortisone