Video Experimental Relacionado

Updated: May 29, 2026

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

Reacciones asiméricas formales [3 + 3]-cicloadición de nitrones con intermediarios electrófilos de vinilcarbenos

Xiaochen Wang¹, Xinfang Xu, Peter Y Zavalij

¹Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742, USA.

Journal of the American Chemical Society

|September 22, 2011

Resumen

Los catalizadores de carboxilato de dirodio (II) sintetizan de manera eficiente las 3,6-dihidro-1,2-oxazinas a partir de nitrones y vinildiazoacetatos. Los catalizadores quirales proporcionan un alto enantiocontrol en estas reacciones de [3+3]-cicloadición, lo que permite una síntesis asimétrica.

Área de la Ciencia:

Química orgánica es la química orgánica.
La catálisis es la catálisis.
Metodología sintética de la metodología sintética.

Sus antecedentes:

Los carbenos metálicos son versátiles intermedios en la síntesis orgánica.
Las reacciones de cicloadición son fundamentales para la construcción de moléculas cíclicas.
Los nitrones son valiosos 1,3-dipolos en la síntesis orgánica.

Objetivo del estudio:

Desarrollar un método catalítico para la síntesis de 3,6-dihidro-1,2-oxazinas.
Para lograr altos rendimientos y enantioselectividad en la reacción de cicloadición.
Para explorar el alcance de la reacción con varios nitrones.

Principales métodos:

Dirhodium (II) carboxilato catalizó la reacción entre nitrones y un β-TBSO sustituido por vinildiazoacetato.
Utilizando carboxilatos quirales de dirodio ligados con N-ftaloil-(S) -aminoácidos para la catálisis asimétrica.
Investigando las reacciones de [3+3]-cicloadición con nitrones acíclicos y cíclicos.

Principales resultados:

Se obtuvieron altos rendimientos de 3,6-dihidro-1,2-oxazinas.
Se logró un excelente control de enantio mediante el uso de catalizadores quirales de dirodio.
La metodología resultó eficaz tanto para los nitrones acíclicos como para los cíclicos.

Conclusiones:

La reacción catalizada por dirodio (II) desarrollada proporciona una ruta eficiente a las 3,6-dihidro-1,2-oxazinas.
Los catalizadores quirales permiten una síntesis altamente enantioselectiva de estos compuestos heterocíclicos.
Este método representa un avance significativo en la química de la cicloadición asimétrica.

Más Videos Relacionados

Preparation of N-(2-alkoxyvinyl)sulfonamides from N-tosyl-1,2,3-triazoles and Subsequent Conversion to Substituted Phthalans and Phenethylamines

Preparation of N-(2-alkoxyvinyl)sulfonamides from N-tosyl-1,2,3-triazoles and Subsequent Conversion to Substituted Phthalans and Phenethylamines

Published on: January 3, 2018

Solid-phase Synthesis of [4.4] Spirocyclic Oximes

Solid-phase Synthesis of [4.4] Spirocyclic Oximes

Published on: February 6, 2019

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.

Nucleophilic Aromatic Substitution: Addition–Elimination (SNAr)

Nucleophilic Aromatic Substitution: Addition–Elimination (S_NAr)

Nucleophilic substitution in aromatic compounds is feasible in substrates bearing strong electron-withdrawing substituents positioned ortho or para to the leaving group. The reaction proceeds via two steps: the addition of the nucleophile and the elimination of the leaving group.
The reaction begins with an attack of the nucleophile on the carbon that holds the leaving group. This results in the delocalization of the π electrons over the ring carbons. The resonance interaction between the...

Nitrosation of Enols

Nitrosation of Enols

The nitrosation reaction is one of the methods of preparing 1,2-diketones. The enol tautomer of the starting ketone reacts with sodium nitrite in hydrochloric acid, generating the 1,2-diketone after hydrolysis.

Conjugate Addition of Enolates: Michael Addition

Conjugate Addition of Enolates: Michael Addition

The attack of a nucleophile at the β carbon of an α,β-unsaturated carbonyl compound is called conjugate addition. Conjugate addition reactions of active methylene compounds, such as β-diketones, β-keto esters, β-keto nitriles, and α-nitro ketones, are called Michael addition reactions.

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...

Electrophilic Aromatic Substitution: Nitration of Benzene

Electrophilic Aromatic Substitution: Nitration of Benzene

The nitration of benzene is an example of an electrophilic aromatic substitution reaction. It involves the formation of a very powerful electrophile, the nitronium ion, which is linear in shape. The reaction occurs through the interaction of two strong acids, sulfuric and nitric acid.