Mediaspace scheduled maintenance: Aug 25, 2026 07:00 - 12:00 AM. During this time, videos will be temporarily unavailable. Check status updates.

Lecture

Synthesis of Citral: Rearrangements and Applications

In course

CH-233: Organic functions and reactions I

Le cours se focalisera sur les composés carbonyles: leur structures, réactivités, et leurs transformations; la réactivité des énols/énolates et leurs réactions fondamentales. L'importance de la compréhension des mécanismes réactionnels, de la chimio-, regi ...

Description

This lecture covers the industrial application of the synthesis of citral, including enol ether formation, Claisen rearrangement, and the Wagner-Meerwein rearrangement. It explores the key role of citral A in the synthesis of Vitamin A and the rearrangements involving hydride and alkyl shifts. Additionally, it discusses the Baeyer-Villiger oxidation, Pinacol rearrangement, Beckmann rearrangement, and the rearrangement of nitrenoids. The lecture also delves into the generation of ketenes through the Wolff rearrangement, highlighting their electrophilic nature and in situ trapping by nucleophiles.

Instructor

Jieping Zhu

Official source

Related concepts (32)

Rearrangement reaction

In organic chemistry, a rearrangement reaction is a broad class of organic reactions where the carbon skeleton of a molecule is rearranged to give a structural isomer of the original molecule. Often a substituent moves from one atom to another atom in the same molecule, hence these reactions are usually intramolecular. In the example below, the substituent R moves from carbon atom 1 to carbon atom 2: Intermolecular rearrangements also take place.

Curtius rearrangement

The Curtius rearrangement (or Curtius reaction or Curtius degradation), first defined by Theodor Curtius in 1885, is the thermal decomposition of an acyl azide to an isocyanate with loss of nitrogen gas. The isocyanate then undergoes attack by a variety of nucleophiles such as water, alcohols and amines, to yield a primary amine, carbamate or urea derivative respectively. Several reviews have been published. The acyl azide is usually made from the reaction of acid chlorides or anydrides with sodium azide or trimethylsilyl azide.

Claisen rearrangement

The Claisen rearrangement is a powerful carbon–carbon bond-forming chemical reaction discovered by Rainer Ludwig Claisen. The heating of an allyl vinyl ether will initiate a [3,3]-sigmatropic rearrangement to give a γ,δ-unsaturated carbonyl, driven by exergonically favored carbonyl CO bond formation (ΔΔHf = -327 kcal·mol−1). The Claisen rearrangement is an exothermic, concerted (bond cleavage and recombination) pericyclic reaction. Woodward–Hoffmann rules show a suprafacial, stereospecific reaction pathway.

Hofmann rearrangement

The Hofmann rearrangement (Hofmann degradation) is the organic reaction of a primary amide to a primary amine with one less carbon atom. The reaction involves oxidation of the nitrogen followed by rearrangement of the carbonyl and nitrogen to give an isocyanate intermediate. The reaction can form a wide range of products, including alkyl and aryl amines. The reaction is named after its discoverer, August Wilhelm von Hofmann, and should not be confused with the Hofmann elimination, another name reaction for which he is eponymous.

Schmidt reaction

In organic chemistry, the Schmidt reaction is an organic reaction in which an azide reacts with a carbonyl derivative, usually an aldehyde, ketone, or carboxylic acid, under acidic conditions to give an amine or amide, with expulsion of nitrogen. It is named after Karl Friedrich Schmidt (1887–1971), who first reported it in 1924 by successfully converting benzophenone and hydrazoic acid to benzanilide. The intramolecular reaction was not reported until 1991 but has become important in the synthesis of natural products.

Related lectures (26)

Rearrangement Chemistry: Sigmatropic and Cationic Rearrangements

Explores sigmatropic and cationic rearrangements, including 1,2-hydride shifts and Baeyer-Villiger oxidation.

Organic Chemistry: Acid-Base Reactions and Electronegativity

Covers acid-base reactions, correct arrowing, electronegativity, and the inductive effect on acid strength.

Asymmetric Catalysis: Sulfa-Michael Addition Mechanism

Covers the mechanism of asymmetric catalysis in sulfa-Michael addition reactions, detailing the role of bifunctional iminophosphorane as a catalyst.

Aromatic Compounds: Reactivity and Substitution

Explores the reactivity of aromatic compounds, including electrophilic addition and substitution reactions, regioselectivity, and reaction examples.

Catalytic Cycloadditions: Enantioselective Strategies