Video Experimental Relacionado
Updated: Jul 26, 2026
13:37
Split-and-pool Synthesis and Characterization of Peptide Tertiary Amide Library
Published on: June 20, 2014
Síntesis organocatalizadora y enantioselectiva de alfa-hidroxifosfonatos por síntesis organocatalizadora y
Sampak Samanta1, Cong-Gui Zhao
1Department of Chemistry, University of Texas at San Antonio, Texas 78249-0698, USA.
Journal of the American Chemical Society
|June 8, 2006
Resumen
Un nuevo catalizador de l-prolina permite una síntesis eficiente de alfa-hidroxifosfonatos terciarios. Este método logra altos rendimientos y una excelente pureza enantiomérica (hasta el 99% ee) para estos importantes compuestos.
Área de la Ciencia:
- Química orgánica es la química orgánica.
- Síntesis asimétrica de síntesis.
- La organocatálisis es una catálisis orgánica.
Sus antecedentes:
- Los alfa-hidroxifosfonatos terciarios son valiosos intermediarios sintéticos. también conocidos como alfa-hidroxifosfonatos.
- El desarrollo de métodos enantioselectivos para su síntesis es crucial.
Objetivo del estudio:
- Desarrollar un método nuevo y eficiente para sintetizar alfa-hidroxifosfonatos terciarios.
- Para lograr altos rendimientos y enantioselectividad utilizando organocatálisis.
Principales métodos:
- Utilizó una nueva reacción cruzada de aldol catalizada por l-prolina.
- Se emplean fosfonatos alfa-ceto y cetonas como materias primas.
Principales resultados:
- Se logró la síntesis de terciarios alfa-hidroxifosfonatos en buenos rendimientos.
- Se obtiene alta pureza enantiomérica, hasta un 99% ee.
- Se demostró la eficacia de la l-prolina como organocatalisador.
Conclusiones:
- La reacción cruzada de aldol catalizada por l-prolina es un método altamente efectivo para la síntesis enantioselectiva de fosfonatos alfa-hidroxi terciarios.
- Este enfoque ofrece una ruta práctica para los compuestos de fosfonato enriquecidos enantioméricamente.
Más Videos Relacionados
Videos de Conceptos Relacionados
01:19Allosteric Proteins-ATCase
Binding sites linkages can regulate a protein's function. For example, enzyme activity is often regulated through a feedback mechanism where the end product of the biochemical process serves as an inhibitor.
Aspartate transcarbamoylase (ATCase) is a cytosolic enzyme that catalyzes the condensation of L-aspartate and carbamoyl phosphate to N-carbamoyl-L-aspartate. This reaction is the first step in pyrimidine biosynthesis. UTP and CTP, the end products of the pyrimidine synthesis pathway,...
Aspartate transcarbamoylase (ATCase) is a cytosolic enzyme that catalyzes the condensation of L-aspartate and carbamoyl phosphate to N-carbamoyl-L-aspartate. This reaction is the first step in pyrimidine biosynthesis. UTP and CTP, the end products of the pyrimidine synthesis pathway,...
01:28Amides to Carboxylic Acids: Hydrolysis
Amides can undergo either acid-catalyzed hydrolysis or base-promoted hydrolysis through a typical nucleophilic acyl substitution. Each hydrolysis requires severe conditions.
Acid-catalyzed hydrolysis:
Hydrolysis of amides under acidic conditions yields carboxylic acids. Since the reaction occurs slowly, hydrolysis requires the conditions of heat.
The mechanism begins with the protonation of the carbonyl oxygen by the acid catalyst. The protonation makes the amide carbonyl carbon more...
Acid-catalyzed hydrolysis:
Hydrolysis of amides under acidic conditions yields carboxylic acids. Since the reaction occurs slowly, hydrolysis requires the conditions of heat.
The mechanism begins with the protonation of the carbonyl oxygen by the acid catalyst. The protonation makes the amide carbonyl carbon more...
01:10Factors Affecting α-Alkylation of Ketones: Choice of Base
α-Alkylation of ketones is achieved in the presence of alkyl halides and a base. The reaction proceeds via the formation of an enolate ion followed by nucleophilic substitution. The choice of base employed is essential as it is the key factor in determining the reaction outcome.
The reaction involving bases like EtO− whose conjugate acid EtOH (pKa = 15.9) is stronger than the ketone (pKa = 19.2) results in an equilibrium mixture with higher ketone concentration. As a consequence, side reactions...
The reaction involving bases like EtO− whose conjugate acid EtOH (pKa = 15.9) is stronger than the ketone (pKa = 19.2) results in an equilibrium mixture with higher ketone concentration. As a consequence, side reactions...
01:07Alkylation of β-Ketoester Enolates: Acetoacetic Ester Synthesis
Acetoacetic ester synthesis is a method to obtain ketones from alkyl halides and β-keto esters. The reaction occurs in the presence of an alkoxide base that abstracts the acidic proton of the β-keto esters. The step results in an enolate ion which is doubly stabilized. The enolate then reacts with an alkyl halide via the SN2 process to produce an alkylated ester intermediate with a new C–C bond. The hydrolysis of the intermediate, followed by acidification, results in an alkylated β-keto acid.
01:14Alkylation of β-Diester Enolates: Malonic Ester Synthesis
Malonic ester synthesis is a method to obtain α substituted carboxylic acids from ꞵ-diesters such as diethyl malonate and alkyl halides.
01:18Amino Acid Catabolism
Microorganisms rely on proteins as an essential carbon and energy source, particularly in environments with limited polysaccharides or lipids. However, proteins are too large to cross the plasma membrane unaided, necessitating enzymatic degradation. Microbes secrete extracellular proteases and peptidases that hydrolyze proteins into peptides, which can then be transported across the membrane. Once inside the cell, intracellular proteases degrade these peptides into free amino acids, which...