Organic Chemistry Reactions Flashcards

Which reaction converts an aldehyde to a cyanohydrin?

Answer: Addition of HCN

HCN adds to the carbonyl of an aldehyde via nucleophilic addition to produce a cyanohydrin (α-hydroxy nitrile).

Which of the following is the best description of Markovnikov's rule for HBr addition to propene?

Answer: Br adds to the more substituted carbon

Markovnikov's rule states the halide (nucleophile) adds to the more substituted carbon, forming the more stable carbocation intermediate.

What reagent is used in ozonolysis to work up the ozonide and obtain aldehydes rather than carboxylic acids?

Answer: Zn/H2O (reductive workup)

Reductive workup with Zn and H2O (or Me2S) cleaves the ozonide to give aldehydes, preventing further oxidation.

In the aldol condensation, what type of intermediate is formed in the first step under basic conditions?

Answer: Enolate ion

Base removes an α-hydrogen to form an enolate, which then acts as the nucleophile attacking the carbonyl of another molecule.

Which reaction mechanism is involved in the saponification of an ester?

Answer: Nucleophilic acyl substitution with OH⁻

Saponification proceeds via nucleophilic acyl substitution where hydroxide attacks the carbonyl carbon, forming a tetrahedral intermediate that expels the alkoxide.

What is the product of treating an alkyl halide with alcoholic KOH at high temperature?

Answer: Alkene via elimination

Alcoholic KOH at high temperature is a classic condition for E2 elimination, producing an alkene.

Which of the following best describes the Claisen rearrangement?

Answer: Concerted [3,3]-sigmatropic rearrangement of an allyl vinyl ether

The Claisen rearrangement is a thermal [3,3]-sigmatropic reaction of allyl vinyl ethers that forms γ,δ-unsaturated carbonyl compounds.