Video Experimental Relacionado
Updated: Jul 15, 2026
06:35
Construction and Systematical Symmetric Studies of a Series of Supramolecular Clusters with Binary or Ternary Ammonium Triphenylacetates
Published on: February 15, 2016
Acoplamiento silencioso de alfa-sulfonamidas orgánicas estereocímicamente definidas y sus nanos
Kevin W Kells1, J Michael Chong
1Guelph-Waterloo Centre for Graduate Work in Chemistry and Biochemistry, Department of Chemistry, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1.
Journal of the American Chemical Society
|December 2, 2004
Resumen
Este estudio introduce un nuevo método para la síntesis de alfa-sulfonamidostananos utilizando tributilstannilmetálicos y arylaldehidos. Los compuestos resultantes se someten a acoplamientos silenciosos, lo que demuestra una alta diastereoselectividad e inversión de configuración.
Área de la Ciencia:
- Química orgánica es la química orgánica.
- Química sintética de la química sintética.
- Química organometálica Química orgánica de los metales.
Sus antecedentes:
- Las sulfonamidas son grupos funcionales cruciales en la química medicinal.
- El acoplamiento silencioso es una reacción vital de formación de enlaces carbono-carbono.
- La síntesis estereoselectiva de compuestos quirales sigue siendo un desafío significativo.
Objetivo del estudio:
- Desarrollar una nueva vía estereoselectiva hacia los alfa-sulfonamidostannos.
- Para explorar la utilidad de estos intermediarios en reacciones de acoplamiento cruzado catalizadas por paladio.
- Para investigar el resultado estereoquímico de las transformaciones sintéticas.
Principales métodos:
- Adición de tributilstanilmetálicos a los derivados de (R) -tert-butanesulfonimina de los arylaldehídos.
- Oxidación de los alfa-sulfinamidostananos intermedios mediante el uso de m-CPBA.
- Acoplamientos de tipo Stille catalizados por Palladio/Cobre con cloruro de benzoilo, empleando el ligando tris ((2,4,6-trimetoxifenil) fosfina.
Principales resultados:
- Se obtienen altas diastereoselectividades (>98% de) en la formación de alfa-sulfinamidostannos.
- Síntesis exitosa de alfa-sulfonamidostananos a través de la oxidación.
- Eficientes acoplamientos Stille que producen los productos deseados con inversión de la configuración en el carbono bencílico.
Conclusiones:
- Se ha establecido un método robusto y estereoselectivo para sintetizar alfa-sulfonamidostananos.
- Los intermediarios desarrollados son valiosos para las reacciones de acoplamiento de Stille.
- La reacción procede con una inversión predecible de la estereoquímica en la posición bencílica.
Videos de Conceptos Relacionados
02:30Stability of Substituted Cyclohexanes
This lesson discusses the stability of substituted cyclohexanes with a focus on energies of various conformers and the effect of 1,3-diaxial interactions.
The two chair conformations of cyclohexanes undergo rapid interconversion at room temperature. Both forms have identical energies and stabilities, each comprising equal amounts of the equilibrium mixture. Replacing a hydrogen atom with a functional group makes the two conformations energetically non-equivalent.
For example, in...
The two chair conformations of cyclohexanes undergo rapid interconversion at room temperature. Both forms have identical energies and stabilities, each comprising equal amounts of the equilibrium mixture. Replacing a hydrogen atom with a functional group makes the two conformations energetically non-equivalent.
For example, in...
02:30Chirality at Nitrogen, Phosphorus, and Sulfur
Chirality is most prevalent in carbon-based tetrahedral compounds, but this important facet of molecular symmetry extends to sp3-hybridized nitrogen, phosphorus and sulfur centers, including trivalent molecules with lone pairs. Here, the lone pair behaves as a functional group in addition to the other three substituents to form an analogous tetrahedral center that can be chiral.
A consequence of chirality is the need for enantiomeric resolution. While this is theoretically possible for all...
A consequence of chirality is the need for enantiomeric resolution. While this is theoretically possible for all...
02:17Structure and Nomenclature of Thiols and Sulfides
Thiols and sulfides are sulfur analogs of alcohols and ethers, respectively, where the sulfur atom takes the place of the oxygen atom. Thus, thiols are generally represented as RSH, where R is an alkyl substituent and —SH is the functional group. On the other hand, in sulfides, the central sulfur atom is bonded to two hydrocarbon groups on either side. Depending upon the type of group, sulfides can be either symmetrical or asymmetrical. Both thiols and sulfides display a bent geometry, similar...
01:28Structures of Carboxylic Acid Derivatives
Structure of Carboxylic Acid Derivatives
Carboxylic acid derivatives contain an acyl group attached to a heteroatom such as chlorine, oxygen, or nitrogen. The carbonyl carbon and oxygen are both sp2-hybridized with an unhybridized p orbital.
The three sp2 orbitals of the carbonyl carbon form three σ bonds, one each with the carbonyl oxygen, the α carbon, and the heteroatom, whereas the other two sp2 orbitals of the carbonyl oxygen are occupied by the lone pairs. Further, the unhybridized p...
Carboxylic acid derivatives contain an acyl group attached to a heteroatom such as chlorine, oxygen, or nitrogen. The carbonyl carbon and oxygen are both sp2-hybridized with an unhybridized p orbital.
The three sp2 orbitals of the carbonyl carbon form three σ bonds, one each with the carbonyl oxygen, the α carbon, and the heteroatom, whereas the other two sp2 orbitals of the carbonyl oxygen are occupied by the lone pairs. Further, the unhybridized p...
01:19Structure of Amines
The hybridized nitrogen atom in amines possesses a lone pair of electrons and is bound to three substituents with a bond angle of around 108°, which is less than the tetrahedral angle of 109.5°. However, the C–N–H bond angle is slightly larger at 112°, with a carbon–nitrogen bond length of 147 pm. This carbon–nitrogen bond length of of amines is longer than the carbon–oxygen bond of alcohols (143 pm) but shorter than alkanes’ carbon–carbon bond (154 pm). These aspects are illustrated in Figure...
01:10Radical Reactivity: Steric Effects
The presence of electron-donating, electron-withdrawing, or conjugating groups adjacent to a radical center, imparts electronic stabilization to the radicals. Examples of such electronically-stabilized radicals are triphenylmethyl, tetramethylpiperidine‐N‐oxide, and 2,2‐diphenyl‐1‐picrylhydrazyl. These radicals are remarkably stable and are known as persistent radicals. Some of the persistent radicals can even be isolated and purified.
Along with electronic factors, steric factors also account...
Along with electronic factors, steric factors also account...