Alpha Halogenation of Ketones

The video tutorial covers the alpha halogenation reaction of ketones, starting with acetone reacting with bromine under acidic conditions. It explains the mechanism where the alpha hydrogen is replaced by bromine, detailing the steps under both acidic and basic conditions. The acidic mechanism involves protonation and conversion to the enol form, while the basic mechanism involves deprotonation to form an enolate ion. The video concludes with practice problems to reinforce the concepts.

What is the major product when acetone reacts with bromine under acidic conditions?

• Acetone with one bromine atom replacing an alpha hydrogen

• Acetone with two bromine atoms replacing alpha hydrogens

• Acetone with no bromine atoms

• Acetone with a hydroxyl group

What is the first step in the mechanism of alpha halogenation under acidic conditions?

• Protonation of the ketone by hydronium ion

• Direct reaction with bromine

• Formation of the enolate ion

• Deprotonation of the alpha hydrogen

In the acidic mechanism, what form does the ketone convert into before reacting with bromine?

• Radical form

• Enol form

• Carbanion form

• Enolate form

What is the intermediate formed during the basic mechanism of alpha halogenation?

• Enolate ion

• Enol

• Carbocation

• Radical

How does the enolate ion react with bromine in the basic mechanism?

• By attacking the bromine molecule

• By losing a proton

• By forming a pi bond

• By forming a radical

In the practice problem under acidic conditions, how many alpha hydrogens are replaced?

• One

• Two

• None

• All

What is the major product when a ketone reacts with excess bromine under acidic conditions?

• Ketone with one bromine atom

• Ketone with two bromine atoms

• Ketone with no bromine atoms

• Ketone with a hydroxyl group

In the practice problem under basic conditions, how many alpha hydrogens are replaced?

• Two

• All

• One

• None

What is the major product when a ketone reacts with excess bromine under basic conditions?

• Ketone with no bromine atoms

• Ketone with a hydroxyl group

• Ketone with two bromine atoms

• Ketone with one bromine atom

Under which conditions can all alpha hydrogens be replaced by bromine?

• Neutral conditions

• Basic conditions

• Acidic conditions

• Both acidic and basic conditions