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Freshman Organic Chemistry I

Yale,, Spring 2011 , Prof. Michael McBride

Updated On 02 Feb, 19

Overview

Mechanism: How Energies and Kinetic Order Influence Reaction Rates - Peculiar Rate Laws, Bond Dissociation Energies, and Relative Reactivities - Rate and Selectivity in Radical-Chain Reactions - Electronegativity, Bond Strength, Electrostatics, and Non-Bonded Interactions - Solvation, H-Bonding, and Ionophores - Brnsted Acidity and the Generality of Nucleophilic Substitution - Nucleophilic Substitution Tools - Stereochemistry, Rate Law, Substrate, Nucleophile - Solvent, Leaving Group, Bridgehead Substitution, and Pentavalent Carbon - Pentavalent Carbon? E2, SN1, E1 - Cation Intermediates. Alkenes: Formation, Addition, and Stability - Carbocations and the Mechanism of Electrophilic Addition to Alkenes and Alkynes - Nucleophilic Participation During Electrophilic Addition to Alkenes - Addition to Form Three-Membered Rings: Carbenoids and Epoxidation.

Epoxide Opening, Dipolar Cycloaddition, and Ozonolysis - Metals and Catalysis in Alkene Oxidation, Hydrogenation, Metathesis, and Polymerization - Isoprenoids, Rubber, and Tuning Polymer Properties - Alkynes. Conjugation in Allylic Intermediates and Dienes - Linear and Cyclic Conjugation Theory. 4n+2 Aromaticity - Aromatic Transition States: Cycloaddition and Electrocyclic Reactions - Electronic and Vibrational Spectroscopy - Functional Groups and Fingerprints in IR Spectroscopy. Precession of Magnetic Nuclei - Medical MRI and Chemical NMR - Diamagnetic Anisotropy and Spin-Spin Splitting - Higher-Order Effects, Dynamics, and the NMR Time Scale.

C-13 and 2D NMR. Electrophilic Aromatic Substitution - Aromatic Substitution in Synthesis: Friedel-Crafts and Moses Gomberg - Triphenylmethyl and an Introduction to Carbonyl Chemistry - Mechanism and Equilibrium of Carbonyl Reactions - Imines and Enamines. Oxidation and Reduction - Oxidation States and Mechanisms - Periodate Cleavage, Retrosynthesis, and Green Chemistry - Measuring Bond Energies: Guest Lecture by Prof. G. Barney Ellison - Green Chemistry. Acids and Acid Derivatives - Acids and Acid Derivatives - Acyl Insertions and [gr]α-Reactivity - [gr]α-Reactivity and Condensation Reactions - Proving the Configuration of Glucose and Synthesizing Two Unnatural Products - Review: Synthesis of Cortisone.

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Lecture 17: Alkynes. Conjugation in Allylic Intermediates and Dienes

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Lecture Details

Freshman Organic Chemistry II (CHEM 125B)Because of their unusual acidity very strong base makes it possible to isomerize an internal acetylene to the less stable terminal isomer. Many chemical reactions may be understood in terms of localized bonds, but the special stability of conjugated systems requires considering delocalized orbitals or "resonance." Equilibrium constants, rates, and regiochemistry in systems involving allylic cations, anions, transition states, and free radicals demonstrate that allylic conjugation is worth about 13 kcalmole. Regioselection in addition of DCl to 1,3-pentadiene reveals rapid collapse of an allylic ion pair. Allylic substitution of bromine can be favored over Br2 addition by using NBS to control Br2 concentration. Diene conjugation is worth much less than allylic conjugation.0000 - Chapter 1. Addition to Acetylenes Regio- and Stereochemistry1405 - Chapter 2. Acidity and Isomerization of Acetylenes2030 - Chapter 3. When Does Conjugation Matter? Allylic Intermediates and Transition States3828 - Chapter 4. Allylic Radicals and Allylic Bromination4757 - Chapter 5. Modest Stabilization of Conjugated DienesComplete course materials are available at the Open Yale Courses website httpoyc.yale.eduThis course was recorded in Spring 2011.