Química de relés de aniones: una táctica efectiva para la síntesis orientada a la diversidad
1Department of Chemistry, Laboratory for Research on the Structure of Matter, and Monell Chemical Senses Center, University of Pennsylvania, Philadelphia, PA 19104, USA. smithab@sas.upenn.edu
Journal of the American Chemical Society
|January 5, 2006
Resumen
Un nuevo método de un solo frasco utiliza la química del relé de aniones (ARC) para un acoplamiento eficiente de la pieza clave. Este proceso permite reacciones secuenciales con epoxidos y electrófilos, creando moléculas complejas en un solo paso.
Área de la Ciencia:
- Química orgánica es la química orgánica.
- Metodología sintética de la metodología sintética.
Sus antecedentes:
- Las reacciones multicomponentes ofrecen rutas sintéticas eficientes.
- La química del relé aniónico proporciona una vía para la funcionalización secuencial.
Objetivo del estudio:
- Desarrollar un protocolo de acoplamiento multicomponente de un solo frasco para el eje de conexión.
- Para aprovechar la química de relés de aniones para nuevas transformaciones sintéticas.
Principales métodos:
- Adición de un anión a un epoxido funcionalizado.
- Inducción de un reordenamiento de 1,4-Brook utilizando disolventes polares.
- Reacción posterior del anión generado con electrófilos.
Principales resultados:
- Desarrollo exitoso de un protocolo de un solo frasco.
- Demostración de la reactividad de aniones secuenciales.
- Formación de arquitecturas moleculares complejas.
Conclusiones:
- El protocolo desarrollado es eficaz para el acoplamiento de la pieza clave.
- La química del relé aniónico es una herramienta poderosa para los químicos sintéticos.
- Este método amplía el alcance de las reacciones multicomponentes.
Videos de Conceptos Relacionados
02:17Reduction 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...
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...
01:16Cycloaddition 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.
01:22Preparation of 1° Amines: Azide Synthesis
Direct alkylation of ammonia produces polyalkylated amines, along with a quaternary ammonium salt. To exclusively prepare primary amines, the azide synthesis method can be used.
Azide ions act as good nucleophiles and react with unhindered alkyl halides to form alkyl azides. Alkyl azides do not participate in further nucleophilic substitution reactions, thereby eliminating the chances of polyalkylated products. Alkyl azides are reduced by hydride-based reducing agents, like lithium aluminum...
Azide ions act as good nucleophiles and react with unhindered alkyl halides to form alkyl azides. Alkyl azides do not participate in further nucleophilic substitution reactions, thereby eliminating the chances of polyalkylated products. Alkyl azides are reduced by hydride-based reducing agents, like lithium aluminum...
01:38Preparation of Amines: Reductive Amination of Aldehydes and Ketones
Carbonyl compounds and primary amines undergo reductive amination first to produce imines, followed by secondary amines in the same reaction mixture, using selective reducing agents like sodium cyanoborohydride or sodium triacetoxyborohydride. Reductive amination produces different degrees of substitution of amines depending on the starting amine substrate.
01:28Preparation of 1° Amines: Gabriel Synthesis
Direct alkylation is not a suitable method for synthesizing amines because it produces polyalkylated products. Gabriel synthesis is the most preferred method to exclusively make primary amines. The method uses phthalimide, which contains a protected form of nitrogen that participates in alkylation only once to predominantly give primary amines.
Strong bases like NaOH or KOH deprotonate the phthalimide to form the corresponding anion, which acts as a nucleophile. Further, the anion attacks an...
Strong bases like NaOH or KOH deprotonate the phthalimide to form the corresponding anion, which acts as a nucleophile. Further, the anion attacks an...
01:26Preparation 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...