Jove
Visualize
Contáctanos

Videos de Conceptos Relacionados

Thermal Electrocyclic Reactions: Stereochemistry01:17

Thermal Electrocyclic Reactions: Stereochemistry

The stereochemistry of electrocyclic reactions is strongly influenced by the orbital symmetry of the polyene HOMO. Under thermal conditions, the reaction proceeds via the ground-state HOMO.
Selection Rules: Thermal Activation
Conjugated systems containing an even number of π-electron pairs undergo a conrotatory ring closure. For example, thermal electrocyclization of (2E,4E)-2,4-hexadiene, a conjugated diene containing two π-electron pairs, gives trans-3,4-dimethylcyclobutene.
Thermal and Photochemical Electrocyclic Reactions: Overview01:26

Thermal and Photochemical Electrocyclic Reactions: Overview

Electrocyclic reactions are reversible reactions. They involve an intramolecular cyclization or ring-opening of a conjugated polyene. Shown below are two examples of electrocyclic reactions. In the first reaction, the formation of the cyclic product is favored. In contrast, in the second reaction, ring-opening is favored due to the high ring strain associated with cyclobutene formation.
Diels–Alder Reaction Forming Bridged Bicyclic Products: Stereochemistry01:29

Diels–Alder Reaction Forming Bridged Bicyclic Products: Stereochemistry

Diels–Alder reactions between cyclic dienes locked in an s-cis configuration and dienophiles yield bridged bicyclic products.
Photochemical Electrocyclic Reactions: Stereochemistry01:26

Photochemical Electrocyclic Reactions: Stereochemistry

The absorption of UV–visible light by conjugated systems causes the promotion of an electron from the ground state to the excited state. Consequently, photochemical electrocyclic reactions proceed via the excited-state HOMO rather than the ground-state HOMO. Since the ground- and excited-state HOMOs have different symmetries, the stereochemical outcome of electrocyclic reactions depends on the mode of activation; i.e., thermal or photochemical.
Selection Rules: Photochemical Activation
[4+2] Cycloaddition of Conjugated Dienes: Diels–Alder Reaction01:16

[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.
Diels–Alder Reaction Forming Cyclic Products: Stereochemistry01:28

Diels–Alder Reaction Forming Cyclic Products: Stereochemistry

The Diels–Alder reaction is one of the robust methods for synthesizing unsaturated six-membered rings. The reaction involves a concerted cyclic movement of six π electrons: four π electrons from the diene and two π electrons from the dienophile.

También podría leer

Artículos Relacionados

Artículos vinculados a este trabajo por autores compartidos, revista y gráfico de citas.

Ordenar por
Same author

A General Approach to <i>geminal</i>-Dimethyl <i>trans</i>-Decalin Terpenoids.

Journal of the American Chemical Society·2026
Same author

A Unified Approach for the Synthesis of Conformationally Locked and sp<sup>2</sup>-sp<sup>3</sup> Fused Hybrids.

Chemistry (Weinheim an der Bergstrasse, Germany)·2026
Same author

Light-controlled disruption of cancer cell dormancy via photoswitchable stress hormone receptor degraders.

Proceedings of the National Academy of Sciences of the United States of America·2026
Same author

Celebrating the 150th Anniversary of the American Chemical Society.

Journal of the American Chemical Society·2026
Same author

Single-position ligand modifications tune CB<sub>2</sub>R activity by targeting the toggle switch.

Chemical science·2026
Same author

Stereodivergent Construction of <i>trans</i>-Decalin-Based Terpenoids.

Journal of the American Chemical Society·2026
JoVE
x logofacebook logolinkedin logoyoutube logo
ACERCA DE JoVE
Visión GeneralLiderazgoBlogCentro de Ayuda JoVE
AUTORES
Proceso de PublicaciónConsejo EditorialAlcance y PolíticasRevisión por ParesPreguntas FrecuentesEnviar
BIBLIOTECARIOS
TestimoniosSuscripcionesAccesoRecursosConsejo Asesor de BibliotecasPreguntas Frecuentes
INVESTIGACIÓN
JoVE JournalMethods CollectionsJoVE Encyclopedia of ExperimentsArchivo
EDUCACIÓN
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab ManualCentro de Recursos para ProfesoresSitio de Profesores
Términos y Condiciones de Uso
Política de Privacidad
Políticas

Video Experimental Relacionado

Updated: May 16, 2026

Facile Preparation of (2Z,4E)-Dienamides by the Olefination of Electron-deficient Alkenes with Allyl Acetate
06:46

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

Published on: June 21, 2017

Ciclización de polieno enantioselectivo catalizado por iridio en ciclización de polieno catalizado por iridio.

Michael A Schafroth1, David Sarlah, Simon Krautwald

  • 1Eidgenössische Technische Hochschule Zürich, HCI H335, 8093 Zürich, Switzerland.

Journal of the American Chemical Society
|December 1, 2012
PubMed
Resumen

Un nuevo método permite la policilización enantioselectiva utilizando catálisis de iridio y ácidos de Lewis. Este enfoque crea eficientemente diversos compuestos policíclicos a partir de alcoholes simples con un alto estereocontrol.

Más Videos Relacionados

Solid-phase Synthesis of [4.4] Spirocyclic Oximes
05:15

Solid-phase Synthesis of [4.4] Spirocyclic Oximes

Published on: February 6, 2019

A Two-Step Protocol for Umpolung Functionalization of Ketones Via Enolonium Species
08:12

A Two-Step Protocol for Umpolung Functionalization of Ketones Via Enolonium Species

Published on: August 16, 2018

Videos de Experimentos Relacionados

Last Updated: May 16, 2026

Facile Preparation of (2Z,4E)-Dienamides by the Olefination of Electron-deficient Alkenes with Allyl Acetate
06:46

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

Published on: June 21, 2017

Solid-phase Synthesis of [4.4] Spirocyclic Oximes
05:15

Solid-phase Synthesis of [4.4] Spirocyclic Oximes

Published on: February 6, 2019

A Two-Step Protocol for Umpolung Functionalization of Ketones Via Enolonium Species
08:12

A Two-Step Protocol for Umpolung Functionalization of Ketones Via Enolonium Species

Published on: August 16, 2018

Área de la Ciencia:

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

Sus antecedentes:

  • Los compuestos policíclicos son motivos estructurales vitales en productos naturales y productos farmacéuticos.
  • El desarrollo de métodos eficientes y estereoselectivos para su síntesis sigue siendo un desafío importante en la química orgánica.

Objetivo del estudio:

  • Desarrollar un método novedoso y altamente enantioselectivo para la construcción de complejos sistemas de anillos carbo- y heteropolicíclicos.
  • Para utilizar los alcoholes alilicos racémicos ramificados fácilmente disponibles como materiales de partida.

Principales métodos:

  • Empleó una combinación de activación con ácido de Lewis y sustitución alilica catalizada por iridio.
  • Se utilizaron alcoholes alilicos ramificados y racémicos, lo que permite un uso directo sin resolución previa.

Principales resultados:

  • Sintetizó con éxito una amplia gama de compuestos carbo y heteropolicíclicos únicos.
  • Se obtuvieron altos rendimientos y una excelente enantioselectividad (≥99% ee) para los productos.
  • Demostró la amplia aplicabilidad de la estrategia de policiclización desarrollada.

Conclusiones:

  • El método desarrollado ofrece una ruta potente y eficiente a las estructuras policíclicas enriquecidas enantioméricamente.
  • Esta estrategia proporciona una herramienta valiosa para acceder a arquitecturas moleculares complejas con alta fidelidad estereoquímica.
  • El uso directo de materiales de partida racémicos simplifica las vías sintéticas y mejora la economía atómica.