Video Experimental Relacionado
Updated: Jun 5, 2026
10:17
Efficient Construction of Drug-like Bispirocyclic Scaffolds Via Organocatalytic Cycloadditions of α-Imino γ-Lactones and Alkylidene Pyrazolones
Published on: February 7, 2019
Quiralidad dinámica de (E) -5-ciclononen-1-ona y su enolato
Katsuhiko Tomooka1, Takayuki Ezawa, Hiroko Inoue
1Institute for Materials Chemistry and Engineering, Kyushu University, Kasuga, Fukuoka 816-8580, Japan. ktomooka@cm.kyushu-u.ac.jp
Journal of the American Chemical Society
|January 27, 2011
Resumen
El estudio encontró que mientras que (E) -5-cyclononen-1-one tiene una débil quiralidad plana, sus enolatos derivados exhiben una fuerte quiralidad plana. Estos enolados se pueden preparar mediante hidrólisis enzimática y actúan como nucleófilos quirales.
Área de la Ciencia:
- Química orgánica es la química orgánica.
- La estereoquímica es la estereoquímica.
- Catalización enzimática por catálisis enzimática.
Sus antecedentes:
- La quiralidad plana es un tipo de quiralidad en la que una molécula es quiral debido a una disposición plana de los átomos.
- Las restricciones topológicas son cruciales para mantener una quiralidad robusta en las moléculas orgánicas.
- Los enolados son intermedios versátiles en la síntesis orgánica, a menudo utilizados como nucleófilos.
Objetivo del estudio:
- Para investigar la quiralidad plana de (E) -5-ciclononen-1-ona y sus enolatos derivados.
- Para explorar la preparación de enolados enriquecidos con enantio utilizando métodos enzimáticos.
- Evaluar la utilidad de estos enolados como nucleófilos quirales en síntesis.
Principales métodos:
- Síntesis de (E)-5-ciclononen-1-one. para el tratamiento de la enfermedad.
- Generación de enolados a partir del (E) -5-ciclononen-1-one.
- Hidrólisis enzimática para la preparación enantioselectiva de los enolados.
- Evaluación de la nucleofilicidad enolado y los resultados estereoquímicos.
Principales resultados:
- (E)-5-ciclononen-1-one exhibe una quiralidad plana limitada debido a una restricción topológica insuficiente.
- Los enolados derivados de (E) -5-ciclononen-1-ona demuestran una robusta quiralidad plana.
- Los enolados enriquecidos con enantio se prepararon con éxito a través de la hidrólisis enzimática.
- Los enolados enriquecidos con enantio funcionan eficazmente como nucleófilos quirales.
Conclusiones:
- Los enolados de (E) -5-ciclononen-1-ona son bloques de construcción quirales muy valiosos.
- La hidrólisis enzimática proporciona una ruta eficiente hacia los enolados quirales planos enantioenriquecidos.
- Estos hallazgos abren nuevas vías para la síntesis asimétrica utilizando nucleófilos quirales planas.
Videos de Conceptos Relacionados
02:05Prochirality
The concept of prochirality leads to the nomenclature of the individual faces of a molecule and plays a crucial role in the enantioselective reaction. It is a concept where two or more achiral molecules react to produce chiral products. A typical process is the reaction of an achiral ketone to generate a chiral alcohol. Here, the achiral reactant reacts with an achiral reducing agent, sodium borohydride, to generate an equimolar mixture of the chiral enantiomers of the product. For example, an...
02:33Stereoisomerism of Cyclic Compounds
In this lesson, we delve into the role of ring conformation and its stability, which determines the spatial arrangement and, consequently, the molecular symmetry and stereoisomerism of cyclic compounds. 1,2-Dimethylcyclohexane is used as a case study to evaluate the possible number of stereoisomers. Here, given the multiple (n = 2) chiral centers, there are 2n = 4 possible configurations that lack a plane of symmetry, as the ring skeleton exists in a non-planar chair conformation. In addition,...
01:17Thermal Electrocyclic Reactions: Stereochemistry
The stereochemistry of electrocyclic reactions is strongly influenced by the orbital symmetry of the polyene HOMO. Under thermal conditions, the reaction proceeds via the ground-state HOMO.
Selection Rules: Thermal Activation
Conjugated systems containing an even number of π-electron pairs undergo a conrotatory ring closure. For example, thermal electrocyclization of (2E,4E)-2,4-hexadiene, a conjugated diene containing two π-electron pairs, gives trans-3,4-dimethylcyclobutene.
Selection Rules: Thermal Activation
Conjugated systems containing an even number of π-electron pairs undergo a conrotatory ring closure. For example, thermal electrocyclization of (2E,4E)-2,4-hexadiene, a conjugated diene containing two π-electron pairs, gives trans-3,4-dimethylcyclobutene.
01:12Stereochemical Effects of Enolization
The chiral α-carbon of the carbonyl compound is the stereocenter of the molecule. As shown in the figure below, when such a carbonyl compound undergoes racemization under an acidic or basic condition, an achiral enol is formed.
01:18Reactivity of Enols
Enols are a class of compounds where a hydroxyl group is attached to a carbon–carbon double bond, which implies that it is a vinyl alcohol. A carbonyl compound with an α hydrogen undergoes keto–enol tautomerism and remains in equilibrium with its tautomer, the enol form. Usually, the keto tautomer is present in a higher concentration than the enol tautomer due to the higher bond energy of C=O compared to C=C. Moreover, the direction of the keto–enol equilibrium is governed by factors like...
01:26Thermal and Photochemical Electrocyclic Reactions: Overview
Electrocyclic reactions are reversible reactions. They involve an intramolecular cyclization or ring-opening of a conjugated polyene. Shown below are two examples of electrocyclic reactions. In the first reaction, the formation of the cyclic product is favored. In contrast, in the second reaction, ring-opening is favored due to the high ring strain associated with cyclobutene formation.