객관식
Which of the following reagents can be used to convert into a ?
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3. Acids and Bases
Organic Chemistry Reactions
객관식
In which of the following organic reactions would be a better choice of halogen reagent than ?
A
Free radical halogenation of methane to produce
B
Bromination of benzene under iron(III) bromide catalysis
C
Electrophilic addition to an alkene to form a vicinal dibromide
D
Allylic bromination using NBS (-bromosuccinimide)
검증된 단계별 안내1
Step 1: Understand the nature of free radical halogenation, which involves the abstraction of a hydrogen atom from an alkane by a halogen radical, followed by halogenation of the resulting alkyl radical. Chlorine radicals are more reactive and less selective than bromine radicals in this process.
Step 2: Recognize that in free radical halogenation of methane, chlorine is often preferred because it reacts faster and can efficiently produce chloromethane, despite lower selectivity compared to bromine.
Step 3: Consider bromination of benzene under iron(III) bromide catalysis, which is an electrophilic aromatic substitution reaction. Here, bromine is preferred because it forms a more stable bromonium ion intermediate and is more selective for aromatic substitution.
Step 4: For electrophilic addition to an alkene to form a vicinal dibromide, bromine is typically used because it adds across the double bond in a stereospecific manner, forming a bromonium ion intermediate. Chlorine is less commonly used due to lower selectivity and different reactivity.
Step 5: In allylic bromination using N-bromosuccinimide (NBS), bromine is specifically used to generate bromine radicals that selectively abstract allylic hydrogens. Chlorine is not used here because it is too reactive and less selective, leading to unwanted side reactions.
