Summary of Acidez de alquinos y alquilación

00:00:00 - 00:10:00

In the YouTube video "Acidez de alquinos y alquilación," the speaker discusses the behavior of alkynes as weak acids when reacted with a strong base, such as sodium hydroxide. Terminal alkynes form carbocations, or carbanions, which are relatively stable due to their triple bonds and hybridized orbital electrons. The carbanion functions as a nucleophile and reacts with an alkyl halide through a SN2 reaction. The speaker also explains the process of alkylating an alkene using a base followed by an alkylating agent. The simplest alkene, acetylene, reacts with sodium to form a carbanion, which then reacts with a halogen to form a new carbon-carbon bond and an alkylated compound. The speaker emphasizes the importance of the electronegativity of the halogen in making the carbon easier to attack and the concerted nature of the reaction.

• 00:00:00 In this section of the YouTube video "Acidez de alquinos y alquilación," the speaker explains how alkynes, specifically terminal alkynes, can function as weak acids when reacted with a strong base such as sodium hydroxide. When this reaction occurs, the nitrogen base forms ammonia as one product, while the other product is a carbocation called a carbanion, which is relatively stable due to the triple bond between the carbons and the hybridized orbital of the electrons. The carbanion can then function as a nucleophile and react with an alkyl halide to form a SN2 reaction. The speaker emphasizes that the electrophilic carbon in the alkyl halide has a partial positive charge, making it attractive to electrons from the nucleophile, and the SN2 reaction is concerted, meaning both the nucleophile and the leaving group depart at the same time.
• 00:05:00 In this section of the YouTube video titled "Acidez de alquinos y alquilación," the speaker explains the process of alkylating an alkene using a base followed by an alkylating agent. They begin with the simplest alkene, acetylene, which has a carbon-carbon triple bond and two hydrogens attached. The speaker then adds a unit of sodium, which acts as a strong base and takes a proton from one of the hydrogens, leaving the carbon with a negative charge. This carbon is then alkylated by reacting it with a halogen, such as bromine. The halogen's electronegativity draws the electrons of the bond towards itself, making the carbon easier to attack by the halogen's free electrons. The bromine leaves, resulting in a new carbon-carbon bond and the formation of an alkylated compound. The speaker then mentions that this reaction is useful in organic synthesis and proceeds to explain another reaction involving a different alkene.
• 00:10:00 In this section of the YouTube video titled "Acidez de alquinos y alquilación," the speaker explains the process of alquilación, or alkylation, of an alquino, or alkene, using the example of a microwave's ring-shaped molecule with resonating electrons. The alkene, which has a hydrogen atom with a proton that is acidic, reacts first with a strong base, sodium, which takes the proton, leaving the carbon atom with a negative charge. The highly electronegative chlorine atom then pulls the two electrons of the carbon-hydrogen bond close to its nucleus, making the carbon atom partially positive and electrophilic. The carbon atom with a negative charge then easily accepts the lone pair of electrons from the electrophilic carbon atom, forming a new bond between the two carbons. The speaker emphasizes the importance of drawing out the chemical structure to better understand the process.