Ch. 22 - Condensation ChemistrySee all chapters
All Chapters
Ch. 1 - A Review of General Chemistry
Ch. 2 - Molecular Representations
Ch. 3 - Acids and Bases
Ch. 4 - Alkanes and Cycloalkanes
Ch. 5 - Chirality
Ch. 6 - Thermodynamics and Kinetics
Ch. 7 - Substitution Reactions
Ch. 8 - Elimination Reactions
Ch. 9 - Alkenes and Alkynes
Ch. 10 - Addition Reactions
Ch. 11 - Radical Reactions
Ch. 12 - Alcohols, Ethers, Epoxides and Thiols
Ch. 13 - Alcohols and Carbonyl Compounds
Ch. 14 - Synthetic Techniques
Ch. 15 - Analytical Techniques: IR, NMR, Mass Spect
Ch. 16 - Conjugated Systems
Ch. 17 - Aromaticity
Ch. 18 - Reactions of Aromatics: EAS and Beyond
Ch. 19 - Aldehydes and Ketones: Nucleophilic Addition
Ch. 20 - Carboxylic Acid Derivatives: NAS
Ch. 21 - Enolate Chemistry: Reactions at the Alpha-Carbon
Ch. 22 - Condensation Chemistry
Ch. 23 - Amines
Ch. 24 - Carbohydrates
Ch. 25 - Phenols
Ch. 26 - Amino Acids, Peptides, and Proteins

Dicarbonyl compounds have the ability to self-condensate through cyclization. When a diketone or dialdehyde self-condensate, the resulting product is called a cyclic enone

Concept #1: Diketones

When a diester self-condensates, the resulting product is called a cyclic β-ketoester

  • This is known as a Dieckmann Condensation or Intramolecular Claisen

Concept #2: Diesters (Dieckmann Condensation)

Practice: Consider the following reaction. Provide a stepwise mechanism to explain the given transformation.

Additional Problems
Complete the following reaction. Pay careful attention to the stereochemistry of the product.
Predict the product of this reaction. 
Heating of compound 1 with sodium hydroxide in water led to isolation of the cyclic product 2. Write a detailed mechanism that explains the conversion of 1 to 2. Show all intermediates!
Draw the mechanism of this reaction.
Predict the product(s) in the following aldol condensation using aqueous sodium hydroxide.
Aldol reactions can be conducted either under basic or acidic reaction conditions. Show the mechanism for the following aldol cyclization.
What is the product of the reaction shown below? a A  b B  c C  d D e none of these
Predict the product(s) in the following aldol condensation using aqueous sodium hydroxide.
Complete the mechanism for the following Dieckmann reaction. Be sure to show arrows to indicate movement of all electrons, write all lone pairs, all formal charges, and all the products for each step. Remember, I said all the products for each step. IF A NEW CHIRAL CENTER IS CREATED IN AN INTERMEDIATE OR THE PRODUCTS, MARK IT WITH AN ASTERISK AND LABEL AS "RACEMIC" IF RELEVANT. IN THE BOX BY EACH SET OF ARROWS, WRITE WHICH OF THE 4 MECHANISTIC ELEMENTS IS INDICATED IN EACH STEP OF YOUR MECHANISM
Show your inderstanding of the following Dieckmann Condensation reaction by showing the full arrow pushing mechanism, including ALL RESONANCE FORMS and predicting the products. 
In the presence of a base such as NaOEt, the following reaction proceeds to form the bicyclic product that is shown below. Some of the carbon atoms have been labeled from 1‐9 in the starting material. Number the atoms in the product that correspond to those numbered in the starting material.
Heating of compound 1 with sodium hydroxide in water led to isolation of the cyclic product 2. Write a detailed mechanism that explains the conversion of 1 to 2. Show all intermediates!
List the reagents A-D in the order necessary to complete the following transformation. 
What is the product of the following reaction?
Draw the condensation product obtained when the following compound is heated in the presence of aqueous sodium hydroxide.
What will be the  major product of the following reaction? Pay careful attention to the stereochemistry of the product.
What is the cyclic product formed in the intramolecular Aldol condensation when the followinga. Ib. IIc. IIId. IV