Sp2024 - Midterm 4 Shabbir Review

Which of the following states is TRUE

• The regioselectivity of the NBS reaction can be explained by Zaitsev's rule, which suggests forming the least substituted double bond

• Sodium in liquid ammonia creates the E-alkene because the cis-alkenyl anion is more stable than the trans alkenyl anion.

• In the hydroboration oxidation of an alkene, the hydrogen atom of borane forms a bond with the most substituted carbon as hydrogen is more electronegative as compared to boron

• Vinylic carbocations are more resonance stabilized.

Which of the following statements is TRUE

• Alkyne anions are good nucleophiles that can perform an SN2 reaction with primary and secondary haloalkanes to make a new carbon-carbon bond

• An enol is less stable than a ketone because the carbon-oxygen double bond is stronger than the carbon-carbon double bond

• The earlier the transition state, the more product character the transition state has

• When oxidizing alkenes with OsO4 followed by NaHSO3, the osmium atom is oxidized.

Rank the following molecules in terms of increasing double bond stability. Least stable to most stable.

• 1,3, 2, 4

• 4, 2, 1, 3

• 2, 4, 1, 3

• 3, 1, 4, 2

• 3, 1, 2, 4

Which of the following sequences of reagents would yield the desired transformation?

• 
• 
• 
• 
• 

Predict the predominant product for the following reaction below. For clarity purposes, when a racemic mixture is formed, only one enantiomer is drawn and "racemic" is written underneath.

• 
• 
• 
• 
• 

Which of the following statement is incorrect about the following molecules?

• Performing ozonolysis on this molecule would form two aldehyde functional groups

• Reacting the following molecule with HBr would result in a tertiary haloalkane

• Hydrogenation of the reactant using palladium as a catalyst would yield a chiral product

• Reacting the molecule with Br2 in the presence of light would result in a racemic mixture

• Reacting the following molecule with NBS in the presence of light would result in a rearranged product.

Identify the reaction that is stereoselective but is NOT regioselective.

• A

• B

• C

• D

Determine the correct starting material for the given transformation below.

• A

• B

• C

• D

Identify the predominant product formed by the following reaction below. For clarity purposes, when a racemic mixture is formed, one enantiomer is drawn and the word racemic is written.

If you choose option F, select both B and C.

• A

• B

• C

• D

• E

Choose the incorrect statement about the following two reactions.

• Reaction 1 has an earlier transition state than reaction 2

• According to Hammond's the transition state of reaction 1 would resemble the reactants

• According to Hammond's the transition state for reaction 2 would resemble the products

• Radical stability likely dictated the regioselectivity of reaction 2

• Radical stability likely dictated the regioselectivity of reaction 1