Video Experimental Relacionado
Updated: Jul 14, 2025
08:56
Synthesis of a Borylated Ibuprofen Derivative Through Suzuki Cross-Coupling and Alkene Boracarboxylation Reactions
Published on: November 30, 2022
2.8K
Estudio experimental y computacional de una dimerización confirmada de borileno a diboreno
Myron Heinz1, Merle Arrowsmith2,3, Julia I Schweizer1
1Institute for Inorganic and Analytical Chemistry, Goethe-Universität Frankfurt am Main, Max-von-Laue-Straße 7, 60438 Frankfurt am Main, Germany.
Journal of the American Chemical Society
|October 6, 2023
Resumen
Los investigadores informan de la primera dimerización directa de los borilenos a los diborenos. Esta reacción implica la abstracción de ligando de fosfina de un precursor de hidroborileno por dihaloboranes, lo que lleva a un mecanismo complejo y autocatalítico.
Área de la Ciencia:
- Química inorgánica
- Química del organoboron
- Química del grupo principal
Sus antecedentes:
- La dimerización de los análogos de carbenos más pesados del grupo 13 a los análogos de alqueno está bien establecida.
- Ha faltado la observación directa de la dimerización del borileno dicoordinado (LRB:) a los diborenos (LRBBRL).
Objetivo del estudio:
- Para presentar la primera observación directa de la dimerización de borileno a diboreno.
- Elucidar el complejo mecanismo de reacción que involucra a los precursores de hidroborileno y los dihaloboranos.
Principales métodos:
- Síntesis de dihidrodiborenos a partir de los precursores tricoordinados del hidroborileno y de los dihaloboranos ácidos de Lewis.
- Caracterización experimental de los productos de reacción y de los intermedios.
- Análisis mecanicista computacional en profundidad utilizando métodos DFT.
Principales resultados:
- Síntesis exitosa de dihidrodiborenos mediante la dimerización formal del borileno.
- Identificación de una vía de reacción compleja que involucra la abstracción del ligando PMe3, las transferencias de haluros y los procesos redox.
- Demostración de un ciclo autocatalítico en el que participan cationes radicales de borileno.
Conclusiones:
- El estudio proporciona la primera evidencia directa de la dimerización del borileno a los diborenos.
- El mecanismo de reacción es complejo y autocatalítico, impulsado por los radicales de boro intermedios.
- Los radicales de boro ([LBXR]•) se proponen como socios de acoplamiento más probables que los borilenos dicoordinados en la formación de diboreno.
Videos de Conceptos Relacionados
03:08Hydroboration-Oxidation of Alkenes
8.3K
In addition to the oxymercuration–demercuration method, which converts the alkenes to alcohols with Markovnikov orientation, a complementary hydroboration-oxidation method yields the anti-Markovnikov product. The hydroboration reaction, discovered in 1959 by H.C. Brown, involves the addition of a B–H bond of borane to an alkene giving an organoborane intermediate. The oxidation of this intermediate with basic hydrogen peroxide forms an alcohol.
8.3K
01:29Diels–Alder Reaction: Characteristics of Dienes
4.1K
The Diels–Alder reaction brings together a diene and a dienophile to form a six-membered ring. Both components have unique characteristics that influence the rate of the reaction.
Characteristics of the diene
Conformation
The simplest example of a diene is 1,3-butadiene, an acyclic conjugated π system. At room temperature, the molecule exists as a mixture of s-cis and s-trans conformers by virtue of rotation around the carbon–carbon single bond. Although the s-trans isomer is...
Characteristics of the diene
Conformation
The simplest example of a diene is 1,3-butadiene, an acyclic conjugated π system. At room temperature, the molecule exists as a mixture of s-cis and s-trans conformers by virtue of rotation around the carbon–carbon single bond. Although the s-trans isomer is...
4.1K
![[4+2] Cycloaddition of Conjugated Dienes: Diels–Alder Reaction](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2Ffiles%2Fmedia%2Fscience-education%2Fscience-education-thumbs%2F12417.jpg&w=3840&q=75)
01:16[4+2] Cycloaddition of Conjugated Dienes: Diels–Alder Reaction
10.3K
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.
10.3K
01:28Stability of Conjugated Dienes
3.4K
Introduction
A comparison of the enthalpies of hydrogenation of dienes reveals that conjugated dienes release less heat on hydrogenation, rendering them more stable than their nonconjugated analogs.
A comparison of the enthalpies of hydrogenation of dienes reveals that conjugated dienes release less heat on hydrogenation, rendering them more stable than their nonconjugated analogs.
3.4K
01:24π Molecular Orbitals of 1,3-Butadiene
9.1K
Conjugated dienes have lower heats of hydrogenation than cumulated and isolated dienes, making them more stable. The enhanced stabilization of conjugated systems can be understood from their π molecular orbitals.
The simplest conjugated diene is 1,3-butadiene: a four-carbon system where each carbon is sp2-hybridized and has an unhybridized p orbital that contains an unpaired electron. According to molecular orbital theory, atomic orbitals combine to form molecular orbitals such that the number...
The simplest conjugated diene is 1,3-butadiene: a four-carbon system where each carbon is sp2-hybridized and has an unhybridized p orbital that contains an unpaired electron. According to molecular orbital theory, atomic orbitals combine to form molecular orbitals such that the number...
9.1K
02:36Regioselectivity and Stereochemistry of Hydroboration
8.2K
A significant aspect of hydroboration–oxidation is the regio- and stereochemical outcome of the reaction.
Hydroboration proceeds in a concerted fashion with the attack of borane on the π bond, giving a cyclic four-centered transition state. The –BH2 group is bonded to the less substituted carbon and –H to the more substituted carbon. The concerted nature requires the simultaneous addition of –H and –BH2 across the same face of the alkene giving syn...
Hydroboration proceeds in a concerted fashion with the attack of borane on the π bond, giving a cyclic four-centered transition state. The –BH2 group is bonded to the less substituted carbon and –H to the more substituted carbon. The concerted nature requires the simultaneous addition of –H and –BH2 across the same face of the alkene giving syn...
8.2K