Video Experimental Relacionado

Updated: Jul 19, 2025

Chemoselective Preparation of 1-Iodoalkynes, 1,2-Diiodoalkenes, and 1,1,2-Triiodoalkenes Based on the Oxidative Iodination of Terminal Alkynes

Chemoselective Preparation of 1-Iodoalkynes, 1,2-Diiodoalkenes, and 1,1,2-Triiodoalkenes Based on the Oxidative Iodination of Terminal Alkynes

Published on: September 12, 2018

Halogenación enzimática de las alquinas terminales

April L Lukowski¹, Felix M Hubert¹, Thuan-Ethan Ngo¹

¹Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California San Diego, La Jolla, California 92093, United States.

Journal of the American Chemical Society

|August 18, 2023

Resumen

Los investigadores descubrieron una nueva enzima, JamD, que instala átomos de halógeno en los extremos de las alquinas. Esta halogenasa dependiente de la flavina tiene una amplia tolerancia al sustrato y muestra potencial como biocatalizador para crear haloalquinas únicas.

Área de la Ciencia:

La bioquímica
Biosíntesis de productos naturales
Enzimología

Sus antecedentes:

Las halogenasas oxidativas suelen instalar halógenos en sistemas aromáticos o conjugados.
Mientras que las alquinas halogenadas existen en la naturaleza, la halogenación enzimática terminal de alquinas no se ha demostrado previamente.
Las vías de biosíntesis de productos naturales ofrecen una rica fuente de nuevas actividades enzimáticas.

Objetivo del estudio:

Descubrir y caracterizar una nueva enzima que cataliza la halogenación terminal de alquinos.
Investigar el alcance y la especificidad del sustrato de la alquinilo halogenasa identificada.
Explorar el potencial de esta enzima como biocatalizador para la síntesis de haloalquinos.

Principales métodos:

Aislamiento y caracterización de la vía biosintética de la jamaicamida.
Ensayos enzimáticos en los que se utiliza JamD purificado con varios sustratos alquinos.
Análisis bioquímico de la cinética de las enzimas y la especificidad del sustrato.
Análisis filogenético para identificar la familia y el origen de la enzima.

Principales resultados:

Descubrimiento de JamD, una halogenasa dependiente de la flavina de la vía jamaicamida.
Demostración de la capacidad de JamD para halogenar alquinas terminales en un intermedio biosintético en etapa tardía.
Identificación de una amplia tolerancia del sustrato para diversas estructuras alquinosas.
Pruebas de la especificidad de JamD para las alquinas terminales sobre sustratos aromáticos.
Clasificación de JamD dentro de una nueva familia de halogenasas de cianobacterias marinas.

Conclusiones:

JamD es la primera enzima caracterizada capaz de la halogenación terminal directa.
Esta enzima representa un nuevo biocatalizador para la síntesis quimioselectiva de las haloalquinas.
El descubrimiento amplía el repertorio conocido de enzimas halogenasa y sus funciones biológicas.

Más Videos Relacionados

Metal-free Synthesis of Ynones from Acyl Chlorides and Potassium Alkynyltrifluoroborate Salts

Metal-free Synthesis of Ynones from Acyl Chlorides and Potassium Alkynyltrifluoroborate Salts

Published on: February 24, 2015

A Two-Step Protocol for Umpolung Functionalization of Ketones Via Enolonium Species

A Two-Step Protocol for Umpolung Functionalization of Ketones Via Enolonium Species

Published on: August 16, 2018

Videos de Conceptos Relacionados

Electrophilic Addition to Alkynes: Halogenation

Electrophilic Addition to Alkynes: Halogenation

Introduction
Halogenation is another class of electrophilic addition reactions where a halogen molecule gets added across a π bond. In alkynes, the presence of two π bonds allows for the addition of two equivalents of halogens (bromine or chlorine). The addition of the first halogen molecule forms a trans-dihaloalkene as the major product and the cis isomer as the minor product. Subsequent addition of the second equivalent yields the tetrahalide.

Electrophilic Addition to Alkynes: Hydrohalogenation

Electrophilic Addition to Alkynes: Hydrohalogenation

Electrophilic addition of hydrogen halides, HX (X = Cl, Br or I) to alkenes forms alkyl halides as per Markovnikov's rule, where the hydrogen gets added to the less substituted carbon of the double bond. Hydrohalogenation of alkynes takes place in a similar manner, with the first addition of HX forming a vinyl halide and the second giving a geminal dihalide.

Preparation of Alkynes: Dehydrohalogenation

Preparation of Alkynes: Dehydrohalogenation

Introduction
Alkynes can be prepared by dehydrohalogenation of vicinal or geminal dihalides in the presence of a strong base like sodium amide in liquid ammonia. The reaction proceeds with the loss of two equivalents of hydrogen halide (HX) via two successive E2 elimination reactions.

Preparation of Alkynes: Alkylation Reaction

Preparation of Alkynes: Alkylation Reaction

Introduction
Alkylation of terminal alkynes with primary alkyl halides in the presence of a strong base like sodium amide is one of the common methods for the synthesis of longer carbon-chain alkynes. For example, treatment of 1-propyne with sodium amide followed by reaction with ethyl bromide yields 2-pentyne.

Alkynes to Aldehydes and Ketones: Hydroboration-Oxidation

Alkynes to Aldehydes and Ketones: Hydroboration-Oxidation

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.

Reduction of Alkynes to cis-Alkenes: Catalytic Hydrogenation

Reduction of Alkynes to cis-Alkenes: Catalytic Hydrogenation

Introduction
Like alkenes, alkynes can be reduced to alkanes in the presence of transition metal catalysts such as Pt, Pd, or Ni. The reaction involves two sequential syn additions of hydrogen via a cis-alkene intermediate.