What would be the major product of a Fricdel-Crafts...

What would be the major product of a Fricdel-Crafts alkylation reaction using the following alkyl halides? a. $\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{Cl}$ b. $\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{Cl}$ c. $\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CH}(\mathrm{Cl}) \mathrm{CH}_{3}$ d. $\left(\mathrm{CH}_{3}\right)_{3} \mathrm{CCH}_{2} \mathrm{Cl}$ e. $\left(\mathrm{CH}_{3}\right)_{2} \mathrm{CHCH}_{2} \mathrm{Cl}$ f. $\mathrm{CH}_{2}=\mathrm{CHCH}_{2} \mathrm{Cl}$

What would be the major product of a Fricdel-Crafts alkylation reaction using the following alkyl halides?
a. $\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{Cl}$
b. $\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{Cl}$
c. $\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CH}(\mathrm{Cl}) \mathrm{CH}_{3}$
d. $\left(\mathrm{CH}_{3}\right)_{3} \mathrm{CCH}_{2} \mathrm{Cl}$
e. $\left(\mathrm{CH}_{3}\right)_{2} \mathrm{CHCH}_{2} \mathrm{Cl}$
f. $\mathrm{CH}_{2}=\mathrm{CHCH}_{2} \mathrm{Cl}$

Key Concepts

Reactivity of Alkyl Halides

The reactivity of alkyl halides in Friedel-Crafts alkylation is determined by their ability to form stable carbocations upon interaction with a Lewis acid catalyst. Primary alkyl halides often form unstable carbocations and can lead to rearrangements or low reactivity, whereas secondary and tertiary alkyl halides form more stable carbocations, making them better substrates for the reaction. Additionally, vinyl and aryl halides are generally unsuitable because the corresponding carbocations are highly unstable.

Carbocation Rearrangement

Carbocation rearrangement involves the migration of atoms or groups (such as hydride or alkyl groups) to form a more stable carbocation from a less stable one. This rearrangement can significantly alter the product distribution in Friedel-Crafts alkylation by leading to unexpected alkylated products.

Carbocation Stability

The stability of carbocations is crucial in Friedel-Crafts alkylation because the reaction proceeds through a carbocation intermediate. Factors such as the degree of substitution (tertiary > secondary > primary) strongly influence the reaction rate and outcome, as more stable carbocations are formed more readily and lead to more efficient alkylation.

Electrophilic Aromatic Substitution

Electrophilic aromatic substitution (EAS) is a core mechanism in organic chemistry where an electrophile replaces a hydrogen atom on an aromatic ring. The process involves the formation of a sigma complex, which briefly disrupts the aromaticity before deprotonation restores the aromatic system.

Friedel-Crafts Alkylation

Friedel-Crafts alkylation is a reaction in which an alkyl group is attached to an aromatic ring via an electrophilic aromatic substitution. This process typically employs a Lewis acid catalyst to generate a reactive carbocation intermediate from an alkyl halide, enabling the aromatic ring to attack the electrophile.

Transcript

00:01 Okay, so i want to give the products for the following fidel crafts, occulation reactions, and in each of these, we're reacting benzene with some different reactant, as well as a catalyst.

00:14 So, the first one, reacting with chlorathene, and this is done with either alcl3 or fecl3, if using chlorine.

00:27 So chlorine is more electronegative than aluminum, so it's going to use a pair of electrons to form a bomb for aluminum and we'll get the structure.

00:41 Chlorians get up a positive charge, making a better leaving group.

00:45 This will be a negative.

00:46 This is going to leave and it's going to leave behind a primary carbon cation and this can't under get a rearrangement because it would be a primary carbon it's on.

01:06 So one of double bonds in the ring is going to attack it.

01:12 Give me this product.

01:13 Next one is with chloropropane and we'll get a primary carbon carbon ion but this time it's going to undergarine arrangement because we would have a secondary carbon on that carbon so we'll get a hydride shift and this is more stable because we have more r groups that act as electron dany groups to stabilize the positive charge and once the dobon attacks the carbonateon we'll get the structure.

02:09 It's an ice purple group.

02:13 Benfercy.

02:14 Reacting benzene with 2 -chlorobutene and they'll sail through.

02:33 So leaving behind a secondary carbocanon, and this can't under get rearrangement because this one's also secondary.

02:41 So it's as stable as gambe.

02:44 And once that attacks the carbureon, we'll get a sec -butal group.

02:56 So sec for secondary and butyl for four carbons.

03:02 Next one is a more hindered carbon.

03:07 So we'll still have a primary carbon cation, but carbon two is more hindered.

03:27 And we'll get a primary carbon cadine...