Video Experimental Relacionado

Updated: Jun 19, 2025

Preparation of Enantiopure Non-Activated Aziridines and Synthesis of Biemamide B, D, and epiallo-Isomuscarine

Preparation of Enantiopure Non-Activated Aziridines and Synthesis of Biemamide B, D, and epiallo-Isomuscarine

Published on: June 13, 2022

Síntesis total concisa de (-) -crinipelinas A y B habilitadas por un reordenamiento controlado de Cargill

Bo Xu¹, Ziyao Zhang¹, Dean J Tantillo²

¹Department of Chemistry, Emory University, Atlanta, Georgia 30322, United States.

Journal of the American Chemical Society

|July 25, 2024

Resumen

Hemos sintetizado productos naturales de diterpenos (-) -crinipellinas A y B, con complejos esqueletos de tetraquinano. Los pasos clave incluyeron la β-alquilación de Kozikowski, la cicloadición fotoquímica [2 + 2] y el reordenamiento de Cargill.

Área de la Ciencia:

Química orgánica
Síntesis de productos naturales
Desarrollo de la metodología química

Sus antecedentes:

Los productos naturales de diterpeno (-) -crinipellinas A y B poseen un esqueleto tetraquinano único.
Estas moléculas contienen tres centros cuaternarios adyacentes de carbono y grupos funcionales sensibles, lo que plantea desafíos sintéticos significativos.

Objetivo del estudio:

Para lograr una síntesis total concisa de las (-) -crinipellinas A y B.
Desarrollar y aplicar nuevas estrategias sintéticas para la construcción de sistemas policíclicos complejos.

Principales métodos:

Síntesis convergente que utiliza la β-alquilación de Kozikowski para ensamblar los bloques de construcción.
Cicloadición fotoquímica intramolecular [2 + 2] para la instalación de centros cuaternarios y núcleos tetraciclicos.
Reorganización controlada de Cargill para alcanzar el esqueleto de tetraquinano objetivo.

Principales resultados:

Síntesis total exitosa de las (-) -crinipellinas A y B en 12 y 13 pasos, respectivamente.
Demostración de una ruta sintética robusta que emplea reacciones clave de formación de enlaces C-C.
Los cálculos químicos cuánticos aclararon las vías mecanicistas para los reordenamientos de Cargill catalizados por ácido y catalizados por AlR3.

Conclusiones:

La estrategia sintética desarrollada proporciona un acceso eficiente a los diterpenos complejos.
El estudio destaca la utilidad de la cicloadición fotoquímica [2 + 2] y el reordenamiento de Cargill en la síntesis de productos naturales.
Las ideas mecánicas sobre el reordenamiento de Cargill ofrecen una comprensión valiosa para futuros esfuerzos sintéticos.

Más Videos Relacionados

Solid-phase Synthesis of [4.4] Spirocyclic Oximes

Solid-phase Synthesis of [4.4] Spirocyclic Oximes

Published on: February 6, 2019

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

Videos de Conceptos Relacionados

Preparation of 1° Amines: Hofmann and Curtius Rearrangement Overview

Preparation of 1° Amines: Hofmann and Curtius Rearrangement Overview

In the presence of an aqueous base and a halogen, primary amides can lose the carbonyl (as carbon dioxide) and undergo rearrangement to form primary amines. This reaction, called the Hofmann rearrangement, can produce primary amines (aryl and alkyl) in high yields without contamination by secondary and tertiary amines.

Preparation of 1° Amines: Hofmann and Curtius Rearrangement Mechanism

Preparation of 1° Amines: Hofmann and Curtius Rearrangement Mechanism

The Hofmann and Curtius rearrangement reactions can be applied to synthesize primary amines from carboxylic acid derivatives such as amides and acyl azides. In the Hofmann rearrangement, a primary amide undergoes deprotonation in the presence of a base, followed by halogenation to generate an N-haloamide. A second proton abstraction produces a stabilized anionic species, which rearranges to an isocyanate intermediate via an alkyl group migration from the carbonyl carbon to the neighboring...

[3,3] Sigmatropic Rearrangement of 1,5-Dienes: Cope Rearrangement

[3,3] Sigmatropic Rearrangement of 1,5-Dienes: Cope Rearrangement

The Cope rearrangement is classified as a [3,3] sigmatropic shift in 1,5-dienes, leading to a more stable, isomeric 1,5-diene. The reaction involves a concerted movement of six electrons, four from two π bonds and two from a σ bond, via an energetically favorable chair-like transition state.

[3,3] Sigmatropic Rearrangement of Allyl Vinyl Ethers: Claisen Rearrangement

[3,3] Sigmatropic Rearrangement of Allyl Vinyl Ethers: Claisen Rearrangement

The Claisen rearrangement is a [3,3] sigmatropic rearrangement of allyl vinyl ethers to unsaturated carbonyl compounds. The rearrangement is a concerted pericyclic reaction proceeding via a chair-like transition state.

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.

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).