Video Experimental Relacionado

Updated: May 4, 2026

Versatile CO2 Transformations into Complex Products: A One-pot Two-step Strategy

Versatile CO2 Transformations into Complex Products: A One-pot Two-step Strategy

Published on: November 9, 2019

Reacciones de doble anulación catiónica enantioselectiva y catalítica útiles iniciadas en un enlace π interno: método

Karavadhi Surendra¹, Goreti Rajendar, E J Corey

¹Department of Chemistry and Chemical Biology, Harvard University , Cambridge, Massachusetts 02138, United States.

Journal of the American Chemical Society

|December 24, 2013

Resumen

Un nuevo método catalítico utiliza un complejo de pentacloruro de dicloro-BINOL-antimonio para la policiclización catiónica enantioselectiva. Este enfoque sintetiza de manera eficiente moléculas policíclicas quirales, incluidos los productos naturales, a partir de enlaces π internos.

Área de la Ciencia:

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

Sus antecedentes:

La síntesis enantioselectiva es crucial para producir moléculas quirales, particularmente productos naturales y productos farmacéuticos.
El desarrollo de métodos catalíticos eficientes para estructuras policíclicas complejas sigue siendo un desafío importante en la química orgánica.

Objetivo del estudio:

Extender la aplicación de la policiclización catiónica enantioselectiva a los enlaces π internos.
Demostrar un método poderoso y versátil para la construcción de marcos quirales policíclicos.
Proporcionar rutas sintéticas simplificadas a productos naturales valiosos y sus análogos.

Principales métodos:

Utilizó un complejo 1:1 de o,o'-dicloro-R-BINOL y pentacloruro de antimonio (SbCl5) como catalizador.
Investigó la policiclización catiónica enantioselectiva de sustratos poliinsaturados con enlaces π terminales e internos.
Desarrolló vías sintéticas directas para el ácido disideapalaúnico, el ácido deshidroabiético y el ácido epipodocarpico.

Principales resultados:

Se ha demostrado con éxito la capacidad del sistema catalítico para llevar a cabo la policiclización enantioselectiva en enlaces π internos.
Logró resultados estereoquímicos predecibles en la formación de moléculas policíclicas quirales.
Proporcionó rutas sintéticas eficientes y cortas para apuntar a productos naturales y compuestos relacionados.

Conclusiones:

El método desarrollado amplía significativamente el alcance de la policiclización catiónica enantioselectiva al permitir el uso de enlaces π internos.
Este enfoque ofrece una poderosa estrategia para la rápida construcción de diversas arquitecturas quirales policíclicas.
La síntesis de ácido disideapalaúnico, ácido deshidroabiético y ácido epipodocarpico pone de relieve la utilidad práctica y el valor de esta metodología enantioselectiva.

Más Videos Relacionados

Highly Stereoselective Synthesis of 1,6-Ketoesters Mediated by Ionic Liquids: A Three-component Reaction Enabling Rapid Access to a New Class of Low Molecular Weight Gelators

Highly Stereoselective Synthesis of 1,6-Ketoesters Mediated by Ionic Liquids: A Three-component Reaction Enabling Rapid Access to a New Class of Low Molecular Weight Gelators

Published on: November 27, 2015

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

Videos de Conceptos Relacionados

Reduction of Alkenes: Asymmetric Catalytic Hydrogenation

Reduction of Alkenes: Asymmetric Catalytic Hydrogenation

Catalytic hydrogenation of alkenes is a transition-metal catalyzed reduction of the double bond using molecular hydrogen to give alkanes. The mode of hydrogen addition follows syn stereochemistry.
The metal catalyst used can be either heterogeneous or homogeneous. When hydrogenation of an alkene generates a chiral center, a pair of enantiomeric products is expected to form. However, an enantiomeric excess of one of the products can be facilitated using an enantioselective reaction or an...

Cyclohexenones via Michael Addition and Aldol Condensation: The Robinson Annulation

Cyclohexenones via Michael Addition and Aldol Condensation: The Robinson Annulation

Robinson annulation is a base-catalyzed reaction for the synthesis of 2-cyclohexenone derivatives from 1,3-dicarbonyl donors (such as cyclic diketones, β-ketoesters, or β-diketones) and α,β-unsaturated carbonyl acceptors. Named after Sir Robert Robinson, who discovered it, this reaction yields a six-membered ring with three new C–C bonds (two σ bonds and one π bond).

Regioselectivity and Stereochemistry of Acid-Catalyzed Hydration

Regioselectivity and Stereochemistry of Acid-Catalyzed Hydration

The rate of acid-catalyzed hydration of alkenes depends on the alkene's structure, as the presence of alkyl substituents at the double bond can significantly influence the rate.

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.

α-Alkylation of Ketones via Enolate Ions

α-Alkylation of Ketones via Enolate Ions

Ketones with α protons are deprotonated by strong bases like lithium diisopropylamide (LDA) to form enolate ions. The anion is stabilized by resonance, and its hybrid structure exhibits negative charges on the carbonyl oxygen and the α carbon. This ambident nucleophile can attack an electrophile via two possible sites: the carbonyl oxygen, known as O-attack, or the α carbon, known as C-attack. The nucleophilic attack via the carbanionic site is preferred. This is due to the...

Acid-Catalyzed α-Halogenation of Aldehydes and Ketones

Acid-Catalyzed α-Halogenation of Aldehydes and Ketones

By replacing an α-hydrogen with a halogen, acid-catalyzed α-halogenation of aldehydes or ketones yields a monohalogenated product
In the first step of the mechanism, the acid protonates the carbonyl oxygen resulting in a resonance-stabilized cation, which subsequently loses an α-hydrogen to form an enol tautomer. The C=C bond in an enol is highly nucleophilic because of the electron-donating nature of the –OH group. Consequently, the double bond attacks an electrophilic...