Quiz - Carbonyl Condensation Reactions - 3 | Carbonyl Condensation Reactions
Organic Chemistry 3 - Quiz - Carbonyl Condensation Reactions - 3
Which mechanism correctly describes the formation of a β-hydroxy carbonyl compound in aldol reactions?
Aldol reactions involve the nucleophilic addition of an enolate ion, formed from a carbonyl compound, to another carbonyl group. This process forms a β-hydroxy carbonyl compound, characteristic of aldol products. The key to this reaction is the formation and reactivity of the enolate ion.
In a crossed aldol reaction, why is it preferred to use a non-enolizable aldehyde?
Using a non-enolizable aldehyde in a crossed aldol reaction helps to avoid self-condensation of the aldehyde, which can lead to a complex mixture of products. This strategic choice ensures selectivity in the reaction, favoring the formation of a single crossed aldol product.
Which characteristic is unique to intramolecular aldol reactions compared to intermolecular aldol reactions?
Intramolecular aldol reactions are distinct in their ability to form cyclic structures, often resulting in a six-membered ring product, which is thermodynamically favored. This distinguishes them from intermolecular aldol reactions, which generally yield acyclic products.
What is the main requirement for the success of the Claisen condensation reaction?
Claisen condensation requires the use of a non-nucleophilic base and an ester with at least one α hydrogen. The non-nucleophilic base ensures that the reaction proceeds via enolate formation without competing nucleophilic reactions that could lead to undesired side products.
What is the principal factor in the Dieckmann cyclization that facilitates ring closure?
The Dieckmann cyclization relies on the proximity of ester groups within a diester compound. This spatial consideration facilitates ring closure as the enolate formed from one ester group attacks the carbonyl carbon of the neighboring ester, leading to cyclization.
Which reaction is characterized by the 1,4-addition of a nucleophile to an α,β-unsaturated carbonyl compound?
The Michael addition is known for the 1,4-addition of a nucleophile to an α,β-unsaturated carbonyl compound. This reaction extends conjugation and creates a bond between the nucleophile and the beta-carbon of the carbonyl system.
In Stork enamine synthesis, what role does the enamine play?
In Stork enamine synthesis, the enamine serves as a Michael donor. It reacts with an α,β-unsaturated carbonyl moiety to form a diketone after hydrolysis.
During enamine alkylation, what step follows the formation of the enamine?
Following the formation of the enamine, alkylation occurs at the alpha position. This step introduces an alkyl group to the carbonyl compound through the nucleophilic character of the enamine. After alkylation, the enamine can be hydrolyzed back to a carbonyl compound with the newly added alkyl group.
What is the result of combining a Michael addition with an aldol condensation in a sequential process?
The Robinson annulation combines a Michael addition with an aldol condensation in a sequential process. This powerful synthetic strategy allows for the construction of complex molecules, including the formation of rings and the introduction of multiple functionalities.
What distinguishes carbonyl condensation reactions from other types of reactions involving carbonyl compounds?
Carbonyl condensation reactions involve the combination of two carbonyl compounds to form a single, more complex molecule.