Section 16.6

(1) Which of the following reagents would best be used to convert benzyl alcohol into an aldehyde?

             A. PCC in CH₂Cl₂

B. Na₂Cr₂O₇ in acid

C. Tollens Reagent

D. LiAlH₄ in ether

E. None of these will carry out this reaction.

(Use the following for questions 2 - 5.) Carbonyl groups are important in organic synthesis because they are highly reactive in a variety of modes. Consider the basic carbonyl structure:

(2) The O end of the C=O bond:

             A. is vulnerable to attack by bases.

B. is vulnerable to attack by acids.

C. can be readily attacked by either acids or bases.

D. is vulnerable to radical attack.

E. is generally inert.

(3) The C end of the C=O bond:

             A. is vulnerable to attack by bases.

B. is vulnerable to attack by acids.

C. can be readily attacked by either acids or bases.

D. is vulnerable to radical attack.

E. is generally inert.

(4) Which of the following gives the most reactive compound?

             A. R1 = R2 = CH₃

B. R1 = H, R2 = CH₃

C. R1 = R2 = Ph

D. R1 = H, R2 = Ph

E. R1 = R2 = H

(5) Which of the following best explains why the answer to the previous question is correct?

             A. Alkyl groups stabilize the charge on the carbonyl carbon.

B. Resonance stabilization is important.

C. The phenyl group(s) holds the system planar for best reaction.

D. The site is less sterically hindered.

E. The O can form a stabilizing intramolecular H-bond.

(6) Rank the following acids in order of increasing acidity.
I. propionic acid II. 3-chloropropionic acid III. Propanol IV. 2-chloropropionic acid

             A. I>II>III>IV

B. IV>III>I>II

C. IV>II>I>III

D. IV>III>II>I

E. III>I>II>IV

(7) Carboxylic acids have higher boiling points than alkanes of similar molecular weights. Which of the following best explains this observation?

             A. Strong dipole/dipole interactions.

B. Stronger than normal dispersive forces.

C. General hydrogen bonding.

D. H-bond dimers.

E. Liquid crystalline packing.

(8) There is a direct relationship between the deactivating strength of a substituent on the ring and the effect that substituent has on the acidity of benzoic acid. Which of the following best explains this observation?

             A. Deactivating groups are able to resonance stabilize the resulting anion.

B. Deactivating strength is tied to steric interference.

C. Deactivating groups are electron withdrawing and thus stabilize the resulting anion by inductive effects.

D. a and b

E. a and c

(9) Addition of a metal hydroxide to a solution of acetic acid followed by evaporation produces which of the following?

             A. CO₂ gas and the purified metal left behind.

B. A peroxide of the acetate and hydroxide anions.

C. No reaction

D. A chelated complex of two acetic acids per metal atom.

E. A soluble metal acetate salt.

(Use the following for questions 10 — 14.) Select from the answer choices below the product of the reaction of an acid chloride (RCOCl) with the reagents/reactions (R) as noted in questions 10 - 14.

(10)

             A. a carboxylic acid

B. an ester

C. an amide

D. an amine

E. no new product

(11)

             A. a carboxylic acid

B. an ester

C. an amide

D. an amine

E. no new product

(12)

             A. a carboxylic acid
B. an ester
C. an amide

D. an amine
E. no new product

(13)

             A. a carboxylic acid

B. an ester

C. an amide

D. an amine

E. no new product

(14)

             A. a carboxylic acid

B. an ester

C. an amide

D. an amine

E. no new product

(Use the following molecule and labels for questions 15 — 16.)

(15) Which of the following statements is correct?

             A. Only protons labeled a, d, and e have enhanced acidity due to resonance effects.

B. Only protons labeled a, b, c, and e have enhanced acidity due to resonance effects.

C. Only protons labeled a, b, and c have enhanced acidity due to resonance effects.

D. Only protons labeled a, b, and c have enhanced acidity due to inductive effects.

E. Only protons labeled a, b, c, and d have enhanced acidity due to inductive effects.

(16) In the compound shown above in (15), which proton is the MOST acidic?

             A.

B.

C.

D.

E.

Use the two molecules below for Question 17 and 18.

(17) Which of the following statements is (are) true?

             A. A is more stable than B.

B. B is more stable than A.

C. Reduction of A by LiAlH₄ leads to B.

D. A is an enolate anion.

E. More than one of the above is true.

(18) Which of the following statements is (are) true?

             A. A and B can be interconverted by a base catalyzed process.

B. A and B can be interconverted by an acid catalyzed process

C. The O atom in A acts as an electrophile in reactions.

D. None of the above is true.

E. More than one of the above is true.

(19) Two mole equivalents of an aldehyde react in an alcoholic sodium ethoxide solution. The reaction name / product pair is:

             A. aldol condensation / b-keto ester

B. Claisen condensation / b-keto ester

C. aldol condensation / b-hydroxy aldehyde

D. Claisen condensation / b-hydroxy aldehyde

E. a mixture of four products

(20) Two mole equivalents of an ester react in an alcoholic sodium ethoxide solution. The reaction name / product pair is:

             A. aldol condensation / b-keto ester

B. Claisen condensation / b-keto ester

C. aldol condensation / b-hydroxy aldehyde

D. Claisen condensation / b-hydroxy aldehyde

E. a mixture of four products

(21) Certain single molecules can contain two aldehyde or two ester groups. If these molecules are mixed with sodium ethoxide in ethanol, what is the result?

             A. Claisen and/or aldol polymers are formed, as the two ends form links to other molecules.

B. If large enough, the molecule will form a ring

C. There are now four possible products and all are formed.

D. There are now eight possible products and all are formed.

E. No reaction occurs under these conditions.

(22) The Michael Reaction can be carried out with a variety of species, yielding a vast variety of products. Which of the following would result in the best reaction with an a,b-unsaturated ketone?

             A. b-keto ester

B. Malonic ester

C. Conjugated enone

D. Nitrile

E. Substituted acetoacetate ester

(23) The Robinson Annulation Reaction results in which of the following?

             A. Stereochemically pure amino acids

B. racemic annulenes

C. polymers

D. multiple fused-ring systems

E. Stereochemically pure annulenes

(24) Which of the following best defines the reactivity of amines?
I. React as Lewis Acids.
II. React as Lewis Bases.
III. Usually accept protons.
IV. Usually donate protons.

             A. I and III

B. I and IV

C. II and III

D. II and IV

E. depending on the pH, all of the above are observed

(25) What is the product of the reaction shown below?

             A. benzene

B. p-nitroaniline

C. an amide

D. a diazonium salt

E. a mixture of products

		A.	PCC in CH₂Cl₂
		B.	Na₂Cr₂O₇ in acid
		C.	Tollens Reagent
		D.	LiAlH₄ in ether
		E.	None of these will carry out this reaction.

		A.	is vulnerable to attack by bases.
		B.	is vulnerable to attack by acids.
		C.	can be readily attacked by either acids or bases.
		D.	is vulnerable to radical attack.
		E.	is generally inert.

		A.	R1 = R2 = CH₃
		B.	R1 = H, R2 = CH₃
		C.	R1 = R2 = Ph
		D.	R1 = H, R2 = Ph
		E.	R1 = R2 = H

		A.	Alkyl groups stabilize the charge on the carbonyl carbon.
		B.	Resonance stabilization is important.
		C.	The phenyl group(s) holds the system planar for best reaction.
		D.	The site is less sterically hindered.
		E.	The O can form a stabilizing intramolecular H-bond.

		A.	I>II>III>IV
		B.	IV>III>I>II
		C.	IV>II>I>III
		D.	IV>III>II>I
		E.	III>I>II>IV

		A.	a carboxylic acid
		B.	an ester
		C.	an amide
		D.	an amine
		E.	no new product

		A.	Only protons labeled a, d, and e have enhanced acidity due to resonance effects.
		B.	Only protons labeled a, b, c, and e have enhanced acidity due to resonance effects.
		C.	Only protons labeled a, b, and c have enhanced acidity due to resonance effects.
		D.	Only protons labeled a, b, and c have enhanced acidity due to inductive effects.
		E.	Only protons labeled a, b, c, and d have enhanced acidity due to inductive effects.

		A.	A is more stable than B.
		B.	B is more stable than A.
		C.	Reduction of A by LiAlH₄ leads to B.
		D.	A is an enolate anion.
		E.	More than one of the above is true.

		A.	A and B can be interconverted by a base catalyzed process.
		B.	A and B can be interconverted by an acid catalyzed process
		C.	The O atom in A acts as an electrophile in reactions.
		D.	None of the above is true.
		E.	More than one of the above is true.

		A.	aldol condensation / b-keto ester
		B.	Claisen condensation / b-keto ester
		C.	aldol condensation / b-hydroxy aldehyde
		D.	Claisen condensation / b-hydroxy aldehyde
		E.	a mixture of four products

		A.	Claisen and/or aldol polymers are formed, as the two ends form links to other molecules.
		B.	If large enough, the molecule will form a ring
		C.	There are now four possible products and all are formed.
		D.	There are now eight possible products and all are formed.
		E.	No reaction occurs under these conditions.

		A.	b-keto ester
		B.	Malonic ester
		C.	Conjugated enone
		D.	Nitrile
		E.	Substituted acetoacetate ester

		A.	Stereochemically pure amino acids
		B.	racemic annulenes
		C.	polymers
		D.	multiple fused-ring systems
		E.	Stereochemically pure annulenes

		A.	I and III
		B.	I and IV
		C.	II and III
		D.	II and IV
		E.	depending on the pH, all of the above are observed

		A.	benzene
		B.	p-nitroaniline
		C.	an amide
		D.	a diazonium salt
		E.	a mixture of products