Video Experimental Relacionado
Updated: Mar 7, 2026
07:36
Versatile CO2 Transformations into Complex Products: A One-pot Two-step Strategy
Published on: November 9, 2019
8.5K
Clasificación del dihidrógeno con el tetra-o-tolil-diborano
Nana Tsukahara1, Hiroki Asakawa1, Ka-Ho Lee2
1Department of Applied Chemistry, Faculty of Science and Engineering, Chuo University , 1-13-27, Kasuga, Bunkyo-ku, 112-8551 Tokyo, Japan.
Journal of the American Chemical Society
|February 8, 2017
Resumen
Se sintetizó y caracterizó el tetra-o-tolil-diborano (4). Este diborano se sometió a la escisión de enlaces B-B y H-H al exponerse al hidrógeno, formando di-tolyl-hidroborano.
Área de la Ciencia:
- Química del organoboron
- Química inorgánica sintética
Sus antecedentes:
- Los diboranos son precursores importantes en la química del organoboron.
- Comprender la reactividad de los diboranos es crucial para el desarrollo de nuevas metodologías sintéticas.
Objetivo del estudio:
- Sintetizar y caracterizar el tetra-o-tolil-diborano (4).
- Investigar la reactividad del tetra-o-tolil-diborano con el gas hidrógeno.
- Para elucidar el mecanismo de reacción utilizando cálculos teóricos.
Principales métodos:
- Síntesis experimental y caracterización del tetra (o-tolyl) diboro (4).
- Reacciones del diborano con el gas hidrógeno en condiciones controladas.
- Cálculos de la teoría funcional de la densidad (DFT) para estudiar la vía de reacción y los estados de transición.
Principales resultados:
- Se sintetizó y caracterizó con éxito el tetra-o-tolil-diborano.
- La exposición al H2 condujo a la escisión de los enlaces H-H y B-B, produciendo di-tolyl-hidroborano.
- Los cálculos de DFT indicaron un carácter de anión diarilborilo en el estado de transición de la reacción.
Conclusiones:
- El tetra ((o-tolyl) diboro ((4) muestra reactividad hacia el H2, sufriendo escisión de enlaces B-B y H-H.
- La reacción procede a través de un mecanismo que implica un estado de transición con un carácter significativo de anión diarilborilo.
- Este estudio proporciona información sobre la reactividad de los diboranos estéricamente obstaculizados.
Videos de Conceptos Relacionados
03:08Hydroboration-Oxidation of Alkenes
11.9K
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.
11.9K
02:47Alkynes to Aldehydes and Ketones: Hydroboration-Oxidation
21.7K
Introduction
One of the convenient methods for the preparation of aldehydes and ketones is via hydration of alkynes. Hydroboration-oxidation of alkynes is an indirect hydration reaction in which an alkyne is treated with borane followed by oxidation with alkaline peroxide to form an enol that rapidly converts into an aldehyde or a ketone. Terminal alkynes form aldehydes, whereas internal alkynes give ketones as the final product.
One of the convenient methods for the preparation of aldehydes and ketones is via hydration of alkynes. Hydroboration-oxidation of alkynes is an indirect hydration reaction in which an alkyne is treated with borane followed by oxidation with alkaline peroxide to form an enol that rapidly converts into an aldehyde or a ketone. Terminal alkynes form aldehydes, whereas internal alkynes give ketones as the final product.
21.7K
01:14Electrophilic 1,2- and 1,4-Addition of X2 to 1,3-Butadiene
3.8K
Electrophilic addition of halogens to alkenes proceeds via a cyclic halonium ion to form a 1,2-dihalide or a vicinal dihalide.
3.8K
![[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
13.4K
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.
13.4K
01:26Radical Substitution: Hydrogenolysis of Alkyl Halides with Tributyltin Hydride
2.3K
Radical substitution reactions can be used to remove functional groups from molecules. The hydrogenolysis of alkyl halides is one such reaction, where the weak Sn–H bond in tributyltin hydride reacts with alkyl halides to form alkanes. Here, the reagent Bu3SnH yields tributyltin halide as a byproduct.
The bonds formed in this reaction are stronger than the bonds broken, making it energetically favorable. The reaction follows a radical chain mechanism similar to radical halogenation reactions,...
The bonds formed in this reaction are stronger than the bonds broken, making it energetically favorable. The reaction follows a radical chain mechanism similar to radical halogenation reactions,...
2.3K
02:36Regioselectivity and Stereochemistry of Hydroboration
9.6K
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 stereochemistry.
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 stereochemistry.
9.6K