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Ch. 15 - Conjugated Systems, Orbital Symmetry, and Ultraviolet Spectroscopy
Wade - Organic Chemistry 9th Edition
Wade9th EditionOrganic ChemistryISBN: 9780135213728Not the one you use?Change textbook
All textbooksWade 9th EditionCh. 15 - Conjugated Systems, Orbital Symmetry, and Ultraviolet SpectroscopyProblem 41c
Chapter 15, Problem 41c

An important variation of the Diels–Alder reaction is intramolecular, in which the diene and the dienophile are connected. This type of Diels–Alder reaction makes two new rings. Draw the compound produced in each of these examples; try to predict stereochemistry (using models will help). In some cases, Lewis acid catalysts are used; that can be ignored for this problem.
(c)

Verified step by step guidance
1
Step 1: Identify the diene and dienophile within the molecule. The diene consists of two conjugated double bonds, while the dienophile is typically an electron-deficient alkene or alkyne. In this structure, the diene is the conjugated system on the left, and the dienophile is the double bond attached to the silicon group (SiMe3).
Step 2: Recognize that this is an intramolecular Diels–Alder reaction. Since the diene and dienophile are part of the same molecule, the reaction will form two new rings. The reaction proceeds via a concerted mechanism, where the π-electrons of the diene interact with the π-electrons of the dienophile.
Step 3: Predict the stereochemistry of the product. The reaction is stereospecific, meaning the stereochemistry of the starting material influences the stereochemistry of the product. The substituents on the diene and dienophile will determine the relative orientation of the newly formed rings. Use molecular models or visualization to predict the stereochemistry.
Step 4: Draw the product structure. The two new rings formed will be fused together, and the stereochemistry of the substituents must be carefully considered. The silicon group (SiMe3) and the oxygen-containing substituents will retain their relative positions based on the reaction mechanism.
Step 5: Verify the product by considering the regiochemistry and stereochemistry. Ensure that the electron flow during the reaction aligns with the formation of the two new rings and that the stereochemistry matches the expected outcome based on the starting material.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Diels–Alder Reaction

The Diels–Alder reaction is a [4+2] cycloaddition reaction between a conjugated diene and a dienophile, resulting in the formation of a six-membered ring. This reaction is significant in organic synthesis due to its ability to create complex cyclic structures efficiently. Understanding the mechanism, including the role of orbital overlap and the formation of new sigma bonds, is crucial for predicting the products and their stereochemistry.
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Intramolecular Reactions

Intramolecular reactions occur when the reactants are part of the same molecule, allowing for a more favorable reaction environment and often leading to the formation of multiple rings. In the context of the Diels–Alder reaction, this means that the diene and dienophile are connected by a linker, which can influence the stereochemistry and the overall product structure. Recognizing how the molecular geometry affects the reaction pathway is essential for accurate predictions.
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Stereochemistry

Stereochemistry refers to the spatial arrangement of atoms in molecules and how this affects their chemical behavior. In the Diels–Alder reaction, the stereochemical outcome is determined by the orientation of the diene and dienophile during the reaction. Predicting stereochemistry involves understanding concepts like cis/trans isomerism and the influence of substituents on the diene and dienophile, which can lead to different stereoisomers in the final product.
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Related Practice
Textbook Question

An important variation of the Diels–Alder reaction is intramolecular, in which the diene and the dienophile are connected. This type of Diels–Alder reaction makes two new rings. Draw the compound produced in each of these examples; try to predict stereochemistry (using models will help). In some cases, Lewis acid catalysts are used; that can be ignored for this problem.

(a)

(b)

1
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Textbook Question

Determine whether each structure is likely to be colored or not. For those that you predict to be colored, indicate the extended conjugation by marking the series of continuous sp2 hybridized atoms.

(i)

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Textbook Question

Determine whether each structure is likely to be colored or not. For those that you predict to be colored, indicate the extended conjugation by marking the series of continuous sp2 hybridized atoms.

(h)

1
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Textbook Question

An important variation of the Diels–Alder reaction is intramolecular, in which the diene and the dienophile are connected. This type of Diels–Alder reaction makes two new rings. Draw the compound produced in each of these examples; try to predict stereochemistry (using models will help). In some cases, Lewis acid catalysts are used; that can be ignored for this problem.

(d)

8
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