Organic Chemistry-III: Claisen & Mannich Reactions

<p>Claisen condensation (D)</p> Signup and view all the answers

<p>Crossed Claisen condensation (D)</p> Signup and view all the answers

<p>Using sodium alkoxide as the base (A)</p> Signup and view all the answers

<p>To generate carbon-carbon bonds (D)</p> Signup and view all the answers

<p>Removal of a proton from the ester product by base (C)</p> Signup and view all the answers

<p>β-amino-carbonyl compound (B)</p> Signup and view all the answers

<p>Lithium ethyl anilide and high dilution techniques (A)</p> Signup and view all the answers

<p>It generates the α-carbanion necessary for the reaction. (A)</p> Signup and view all the answers

<p>Nucleophilic addition followed by dehydration (B)</p> Signup and view all the answers

<p>A β-keto ester. (A)</p> Signup and view all the answers

<p>A secondary amine, formaldehyde, and an enolizable aldehyde or ketone. (C)</p> Signup and view all the answers

<p>Formation of cyclopentanone and cyclohexanone derivatives (B)</p> Signup and view all the answers

<p>It can lead to extra unwanted reactions. (C)</p> Signup and view all the answers

<p>Claisen condensation involves two esters instead of aldehydes or ketones. (D)</p> Signup and view all the answers

<p>The ester will undergo hydrolysis instead of condensation. (C)</p> Signup and view all the answers

<p>A variation of Claisen condensation with diesters. (C)</p> Signup and view all the answers

<p>It cannot enolize. (B)</p> Signup and view all the answers

<p>Formation of a carbanion via abstraction of α-hydrogen. (A)</p> Signup and view all the answers

<p>Dimers of the original carbon chain (B)</p> Signup and view all the answers

<p>It acts as a nucleophile. (B)</p> Signup and view all the answers

<p>The negatively charged oxygen reforms a carbon-oxygen double bond. (B)</p> Signup and view all the answers

<p>Synthesis of flavones (B)</p> Signup and view all the answers

<p>To prevent the formation of byproducts through trans-esterification. (D)</p> Signup and view all the answers

<p>Thiamine (Vitamin B1) (D)</p> Signup and view all the answers

<p>A proton must be removed from the β-keto ester. (B)</p> Signup and view all the answers

<p>Oxalyl derivatives (D)</p> Signup and view all the answers

<p>Nucleophilic substitution reaction. (A)</p> Signup and view all the answers

<p>It obtains a proton from the solvent. (B)</p> Signup and view all the answers

<p>It utilizes an intramolecular process. (B)</p> Signup and view all the answers

<p>They both have carbonyl groups but differ in structure. (C)</p> Signup and view all the answers

<p>α-keto acids (C)</p> Signup and view all the answers

<p>Aromatic aldehydes (D)</p> Signup and view all the answers

<p>It drives the reaction toward the formation of products. (C)</p> Signup and view all the answers

<p>They both have carbonyl groups at the end of the chain. (C)</p> Signup and view all the answers

<p>Dieckmann has intramolecular processes. (C)</p> Signup and view all the answers

<p>With ethyl nicotinate (B)</p> Signup and view all the answers

<p>Synthesis of phenobarbitone (A)</p> Signup and view all the answers

<p>1,6-diester (C)</p> Signup and view all the answers

A reaction where two ester molecules are joined together in the presence of a strong base, such as sodium alkoxide, to form a β-keto ester. The reaction involves the formation of an enolate ion from one ester molecule, which acts as a nucleophile to attack the carbonyl group of another ester molecule.

A Claisen condensation where two different ester molecules are used. The reaction involves the formation of two different enolate ions, leading to a mixture of products.

A special case of the Claisen condensation that involves the intramolecular reaction of a diester. The resulting product is a cyclic β-keto ester.

A reaction that involves the condensation of an aldehyde or ketone with an enamine. This reaction forms a new carbon–carbon bond and provides a convenient way to synthesize β-amino carbonyl compounds.

A step in the mechanism of the Mannich reaction where the enamine attacks the carbonyl group of an aldehyde or ketone, forming an intermediate that then undergoes a proton transfer to yield the final product.

The final step in the Mannich reaction mechanism, where the intermediate undergoes protonation to release the β-amino carbonyl compound.

Mannich reactions where chiral starting materials and catalysts are used, leading to the formation of enantiomerically enriched products.

A specific type of Claisen Condensation that occurs when two diesters react, resulting in a cyclic β-keto ester.

The process of removing a proton from an α-carbon atom in a molecule to form an enolate anion.

A negative ion that results from the removal of a proton from the α-carbon of an aldehyde or ketone.

A chemical that can donate a proton (H+).

A chemical that can readily accept a proton (H+).

A chemical that can act as either an acid or a base.

A type of reaction that involves the addition of a nucleophile to a carbonyl group.

A reaction involving two ester molecules joining to form a β-keto ester, facilitated by a strong base like sodium alkoxide.

In Claisen condensation, the enolate ion of one ester molecule attacks the carbonyl carbon of another ester molecule.

The negatively charged oxygen in the Claisen condensation reforms a carbon-oxygen double bond, expelling the alkoxy group.

The Claisen condensation is a nucleophilic substitution reaction because the enolate ion attacks the carbonyl group, replacing the alkoxy group.

The alkoxide ion used as a base in the Claisen condensation must match the alcohol part of the ester. Using a different alkoxide can lead to a mixture of products through transesterification.

A special case of the Claisen condensation where the molecule has two ester groups and the reaction forms a cyclic β-keto ester.

The Mannich reaction involves the condensation of an aldehyde or ketone with an enamine to form a β-amino carbonyl compound.

The enamine, a nucleophile, attacks the carbonyl group of the aldehyde or ketone, forming an intermediate that undergoes proton transfer to yield the final product.

In the last step of the Mannich reaction, the intermediate undergoes protonation to release the β-amino carbonyl compound.

Mannich reactions using chiral starting materials and catalysts can produce enantiomerically enriched products.

A six-membered ring β-keto ester formed by the intramolecular condensation of a diester.

This reaction is used to build up five or six membered rings in the synthesis of various natural products.

A condensation reaction which involves a nucleophilic addition of an amine to a carbonyl group followed by dehydration to a Schiff base.

A type of Claisen condensation where one reactant is ethyl benzoate, leading to the formation of β-keto esters with an aromatic ring attached.

A reaction involving ethyl benzoate and a ketone to form a flavone, a type of natural product with a characteristic ring structure containing a pyrone ring.

A strategy where a Crossed Claisen condensation involves ethyl nicotinate as one reactant, resulting in the production of the alkaloid nicotine.

A type of Claisen condensation where ethyl formate is used as a reactant, enabling the introduction of a formyl group (CHO) into a molecule.

A specific example of formylation using Crossed Claisen condensation, where ethyl formate is involved in the synthesis of the natural product, equilenine.

A variation of the Claisen reaction where a ketone and diethyl oxalate react, producing oxalyl derivatives, which can be further transformed into synthetically valuable compounds.

A specific example of the Crossed Claisen Condensation with Diethyl Oxalate, where a phenyl-substituted malonic ester is produced, having critical synthetic applications.

A specific example of the Dieckmann condensation, where dimethyl hexanedioate is used as the reactant to produce a cyclic β-keto ester.

A type of Claisen condensation where the nucleophilic attack occurs on a carbonyl group belonging to the same molecule, resulting in the formation of a cyclic β-keto ester.