Video Experimental Relacionado

Updated: Jun 8, 2026

Facile Preparation of (2Z,4E)-Dienamides by the Olefination of Electron-deficient Alkenes with Allyl Acetate

Facile Preparation of (2Z,4E)-Dienamides by the Olefination of Electron-deficient Alkenes with Allyl Acetate

Published on: June 21, 2017

Reacción de cicloadición enantioselectiva [2 + 2 + 2] de isocianatos y alenos catalizados por el níquel

Tomoya Miura¹, Masao Morimoto, Masahiro Murakami

¹Department of Synthetic Chemistry and Biological Chemistry, Kyoto University, Katsura, Kyoto 615-8510, Japan.

Journal of the American Chemical Society

|September 16, 2010

Resumen

Este estudio introduce una reacción de cicloadición catalizada por níquel para sintetizar dihidropirimidina-2,4-dionas quirales a partir de isocyanatos y alenos. El método produce eficientemente compuestos enriquecidos enantioméricamente.

Área de la Ciencia:

Química orgánica es la química orgánica.
La catálisis de la catálisis.
Síntesis asimétrica de síntesis.

Sus antecedentes:

Las dihidropirimidinas-2,4-dionas son valiosos compuestos heterocíclicos.
La síntesis eficiente de formas enriquecidas enantioméricamente sigue siendo un desafío.

Objetivo del estudio:

Desarrollar un método catalítico enantioselectivo para la síntesis de dihidropirimidina-2,4-diones.
Para utilizar materiales de partida fácilmente disponibles como los isocyanatos y los alenos.

Principales métodos:

Empleando un catalizador de níquel (((0) coordinado con un ligando quiral ((S,S) -i-Pr-FOXAP).
Realización de una reacción de cicloadición intermolecular [2 + 2 + 2] entre dos moléculas de isocyanato y una molécula de aleno.

Principales resultados:

La reacción produjo con éxito una dihidropirimidina enriquecida enantioméricamente de 2,4-diones.
Se logró una alta eficiencia y enantioselectividad utilizando el sistema catalítico desarrollado.

Conclusiones:

La cicloadición enantioselectiva catalizada por el níquel ofrece una ruta efectiva hacia la dihidropirimidina-2,4-diones quirales.
Esta metodología proporciona una herramienta valiosa para la síntesis asimétrica en química orgánica.

Más Videos Relacionados

A Direct, Regioselective and Atom-Economical Synthesis of 3-Aroyl-N-hydroxy-5-nitroindoles by Cycloaddition of 4-Nitronitrosobenzene with Alkynones

A Direct, Regioselective and Atom-Economical Synthesis of 3-Aroyl-N-hydroxy-5-nitroindoles by Cycloaddition of 4-Nitronitrosobenzene with Alkynones

Published on: January 21, 2020

Synthesis of Hypervalent Iodonium Alkynyl Triflates for the Application of Generating Cyanocarbenes

Synthesis of Hypervalent Iodonium Alkynyl Triflates for the Application of Generating Cyanocarbenes

Published on: September 8, 2013

Videos de Conceptos Relacionados

Cycloaddition Reactions: Overview

Cycloaddition Reactions: Overview

Cycloadditions are one of the most valuable and effective synthesis routes to form cyclic compounds. These are concerted pericyclic reactions between two unsaturated compounds resulting in a cyclic product with two new σ bonds formed at the expense of π bonds. The [4 + 2] cycloaddition, known as the Diels–Alder reaction, is the most common. The other example is a [2 + 2] cycloaddition.

[4+2] Cycloaddition of Conjugated Dienes: Diels–Alder Reaction

[4+2] Cycloaddition of Conjugated Dienes: Diels–Alder Reaction

The Diels–Alder reaction is an example of a thermal pericyclic reaction between a conjugated diene and an alkene or alkyne, commonly referred to as a dienophile. The reaction involves a concerted movement of six π electrons, four from the diene and two from the dienophile, forming an unsaturated six-membered ring. As a result, these reactions are classified as [4+2] cycloadditions.

Cycloaddition Reactions: MO Requirements for Thermal Activation

Cycloaddition Reactions: MO Requirements for Thermal Activation

Thermal cycloadditions are reactions where the source of activation energy needed to initiate the reaction is provided in the form of heat. A typical example of a thermally-allowed cycloaddition is the Diels–Alder reaction, which is a [4 + 2] cycloaddition. In contrast, a [2 + 2] cycloaddition is thermally forbidden.

Cycloaddition Reactions: MO Requirements for Photochemical Activation

Cycloaddition Reactions: MO Requirements for Photochemical Activation

Some cycloaddition reactions are activated by heat, while others are initiated by light. For example, a [2 + 2] cycloaddition between two ethylene molecules occurs only in the presence of light. It is photochemically allowed but thermally forbidden.

Preparation of Nitriles

Preparation of Nitriles

One of the common methods to prepare nitriles is the dehydration of amides. This method requires strong dehydrating agents like phosphorous pentoxide or boiling acetic anhydride for converting amides to nitriles. Another reagent namely, thionyl chloride also accomplishes the dehydration of amides, where amide acts as a nucleophile. The first step of the mechanism involves the nucleophilic attack by the amide on the thionyl chloride to form an intermediate. In the next step, the electron pairs...

Nucleophilic Aromatic Substitution: Elimination–Addition

Nucleophilic Aromatic Substitution: Elimination–Addition

Simple aryl halides do not react with nucleophiles. However, nucleophilic aromatic substitutions can be forced under certain conditions, such as high temperatures or strong bases. The mechanism of substitution under such conditions involves the highly unstable and reactive benzyne intermediate. Benzyne contains equivalent carbon centers at both ends of the triple bond, each of which is equally susceptible to nucleophilic attack. This 50–50 distribution of products is confirmed through isotopic...