Dienes and MO Theory

Stereochemistry of the Diels-Alder Reaction

Stereochemistry of the Diels-Alder Reaction

November 13, 2017

Here’s what we’ve learned about the Diels Alder reaction so far: [previous post in this series] 3 pi bonds are always broken 2 sigma bonds and a pi bond are always formed, resulting in a new six-membered r…

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Cyclic Dienes and Dienophiles in the Diels-Alder Reaction

Cyclic Dienes and Dienophiles in the Diels-Alder Reaction

September 8, 2017

Last post in this series we introduced the Diels-Alder reaction. We saw that no matter how complex the diene or dienophile, or no matter what substituents are attached, the pattern of bonds that form and break are alw…

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The Diels-Alder Reaction

The Diels-Alder Reaction

August 30, 2017

Today we’ll introduce  a reaction I consider to be the most useful and powerful reaction in all of organic chemistry: the Diels-Alder reaction. But don’t take some random blogger’s word for it. Her…

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s-cis and s-trans

s-cis and s-trans

May 12, 2017

s-cis and s-trans. What does those terms mean? Recall cis and trans. The reason Aldrich Chemical Co. can sell 99% cis-2-butene and 99% trans-2-butene in separate bottles is because of restricted rotation about the …

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More On 1,2 and 1,4 Additions To Dienes

More On 1,2 and 1,4 Additions To Dienes

April 11, 2017

In the last post we covered 1,2 and 1,4 additions to dienes, specifically the addition of strong acid (e.g. HCl or HBr) to dienes. To recap: In Org 1 we learned that addition of HCl and HBr to normal, isolated alkenes…

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Reactions of Dienes: 1,2 and 1,4 Addition

March 22, 2017

In today’s post we’ll discuss  1,2- and 1,4- addition to dienes – specifically, the addition of strong acid such as HBr. Here’s the summary of the key points.  Addition To Alkenes, Revisited …

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Pi Molecular Orbitals of Butadiene

February 28, 2017

In the last post in this series we built up the pi molecular orbitals of the allyl pi-system, consisting of three consecutive p orbitals in conjugation. We saw that: The number of molecular orbitals (n) for a pi-syst…

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Molecular Orbitals of The Allyl Cation, Allyl Radical, and Allyl Anion

Molecular Orbitals of The Allyl Cation, Allyl Radical, and Allyl Anion

February 16, 2017

In the last post, we showed how to build a molecular orbital (MO) diagram for a typical C-C pi bond. We saw that: The number of molecular orbitals equalled the number of contributing atomic orbitals. The overlap of …

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Molecular Orbital Diagram For A Simple Pi Bond – Bonding And Antibonding

Molecular Orbital Diagram For A Simple Pi Bond – Bonding And Antibonding

February 14, 2017

In the previous post in this series, “On Conjugation and Resonance“, I warned that in order to gain a deeper understanding of some of the concepts ahead, we’re going to need to go into MO theory. Bu…

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Conjugation and Resonance

Conjugation and Resonance

January 24, 2017

On Conjugation And Resonance This is the first in a series of posts that will eventually cover conjugation, pi systems, molecular orbital theory, dienes, 1,2- and 1,4- additions, the Diels Alder reaction and other per…

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