Organic Chem 2

Front 1

How many signals are expected in a 13C NMR spectrum of methylcyclohexane?

Back 1

5

Front 2

The 1H NMR spectrum of a compound is shown below. What is the structure of the compound?

Back 2

this

Front 3

Rank the following alkyl radicals in order of increasing stability (least < < most)

Back 3

1 < 3 < 4 < 2

Front 4

What is the major product of the following reaction?

Back 4

this

Front 5

Consider the reaction of 2-methylpropane with a halogen. With which halogen will the product bealmost exclusively 2-halo-2-methylpropane?

Back 5

Br2

Front 6

Identify the reagent(s) that will promote the following transformation.

Back 6

B) HBr, peroxides

Front 7

Which of the following statements regarding 1,2- or 1,4-conjugate addition of HBr to 1,3-butadiene isFALSE?

A) The kinetic product, 3-bromo-1-butene, arises from the more stable carbocation intermediate.

B) The thermodynamic product, 1-bromo-2-butene, is the more stable product.

C) The kinetic product is favored by carrying out the reaction at high temperature.

D) Formation of the two products arises from a common resonance stabilized carbocation intermediate.

Back 7

C) The kinetic product is favored by carrying out the reaction at high temperature.

Front 8

What is the major product of the following reaction?

Back 8

this

Front 9

What are the reactants needed to accomplish the following reaction?

Back 9

this

Front 10

Which of the following compounds are aromatic?

Back 10

a, b, and d

Front 11

Which compounds give a 1H NMR spectrum with two signals in a ratio of 2:3?

a. CH3CH2Cl;

b. CH3CH2CH3;

c. CH3CH2OCH2CH3;

d. CH3OCH2CH2OCH3

Back 11

a, c, d only

Front 12

Rank the following compounds in the order of increasing λmax

Back 12

B

Front 13

In comparing kinetic control to thermodynamic control for the reaction of butadiene and HCl, which ofthe following statements represents kinetic control?

A. The intermediate is more stable and the product is more stable.

B. The intermediate is less stable and the product is more stable.

C. The intermediate is more stable and the product is less stable.

D. The intermediate is less stable and the product is less stable.

Back 13

C. The intermediate is more stable and the product is less stable.

Front 14

The best sequence to use to form propylbenzene from benzene is

A. Friedel–Crafts alkylation using 1-chloropropane and aluminum trichloride.

B. Friedel–Crafts acylation followed by reduction.

C. Electrophilic addition of 1-chloropropane.

D. Nucleophilic aromatic substitution using propyl Grignard.

Back 14

B. Friedel–Crafts acylation followed by reduction.

Front 15

6. What is the electrophile in the electrophilic substitution reaction of benzene using HNO3 and H2SO4?

A. SO3

B. NO3

C. NO2+

D. NO+

Back 15

C. NO2 +

Front 16

Predict the major product of the following reaction.

Back 16

m-nitrobenzaldehyde

Front 17

Rank the following compounds in order of increasing reactivity in electrophilic aromatic substitution

Back 17

Y

Front 18

Which of the following compounds is the most acidic?

CH3COOH;

H2SO4;

CH3OH;

HF

Back 18

H2SO4

Front 19

Which of the following compounds does NOT give benzoic acid when heated with alkaline potassiumpermanganate?

A. tert-Butylbenzene

B. Ethylbenzene

C. Toluene

D. Styrene

Back 19

A. tert-Butylbenzene

Front 20

Which of the following statements about organometallic compounds is FALSE?

A. Alkyllithium reagents (RLi) add to the carbonyl group of aldehydes and ketones.

B. Grignard reagents (RMgBr) add to the carbonyl group of aldehydes and ketones.

C. Alkyllithium and Grignard reagents do not add to esters.

D. Grignard reagents are prepared in ether or tetrahydrofuran (THF).

Back 20

C. Alkyllithium and Grignard reagents do not add to esters.

Front 21

Arrange the following compounds in order of decreasing chemical shift for the underlined hydrogens(largest δ value first, smallest value last).

a) CH3OCH2CH3;

b) CH3CH2CH3;

c) Cl2CHCH2CH3;

d) ClCH2CH2CH3

Back 21

a > c > d > b

Front 22

Which of the following statements regarding the Diels–Alder reaction is TRUE?

A) The diene must be s-cis and the major product is usually the endo product.

B) The diene must be s-trans and the major product is the endo product.

C) The diene must be s-cis and the major product is the exo product.

D) The diene must be s-trans and the major product is the exo product.

Back 22

A) The diene must be s-cis and the major product is usually the endo product.

Front 23

When benzene undergoes hydrogenation in the presence of a catalyst, the energy that is released (the heat ofhydrogenation) is

A) the same as for cyclohexatriene.

B) the same as for 1,3-cyclohexadiene.

C) the same as for 1,4-cyclohexadiene.

D) less than for 1,3-cyclohexadiene.

Back 23

D) less than for 1,3-cyclohexadiene.

Front 24

Which of the following aromatic compounds undergoes Friedel–Crafts alkylation with methyl chloride andaluminum chloride?

A) benzoic acid

B) nitrobenzene

C) aniline

D) toluene

Back 24

D) toluene

Front 25

Which of the following compounds does NOT give a tertiary alcohol upon reaction with excessmethylmagnesium bromide?

A) 3-methylpentanal

B) ethyl benzoate

C) 4,4-dimethylcyclohexanone

D) 4-heptanone

Back 25

A) 3-methylpentanal

Front 26

Predict which of the following compounds will have a lower boiling point than 1-butanal.

A) 1-butanol

B) 2-butanol

C) 1-butene

D) butanoic acid

Back 26

C) 1-butene

Front 27

What ylide is needed to make 3-ethyl-3-heptene from 3-pentanone in a Wittig reaction?

A) Ph3P=CH-CH2-CH3

B) Ph3P=CH(CH2CH3)2

C) Ph3P=CH-CH2CH2CH3

D) Ph3P=CH2

Back 27

C) Ph3P=CH-CH2CH2CH3

Front 28

Which of the following compounds will react most rapidly with water?

A) acetone

B) acetyl chloride

C) acetic anhydride

D) ethyl acetate

Back 28

B) acetyl chloride

Front 29

What is the product formed when benzonitrile is treated with phenylmagnesium bromide followed by acidhydrolysis?

A) benzophenone

B) benzyl alcohol

C) benzaldehyde

D) triphenylmethyl amine

Back 29

A) benzophenone

Front 30

Which compound is formed when the enolate of 2-methylcyclohexanone, formed from lithiumdiisopropylamide (LDA), reacts with methyl iodide?

Back 30

B

Front 31

What is the name of the following compound?

Back 31

lithium diisopropylamide

Front 32

Predict the product of the following reaction. Benzenediazonium chloride + CuCN →

A) Ph2CuCl

B) Ph–CN

C) Ph2CuLi

D) Ph–N=N–CN

Back 32

B) Ph–CN

Front 33

Which of the following compounds form the highest percentage of gem-diol at equilibrium?

A) CH3CH2CH2CHO

B) CH3CH2COCH3

C) CH3CF2CHO

D) CH3CH2CHO

Back 33

C) CH3CF2CHO

Front 34

Rank the following compounds in order of increasing reactivity in nucleophilic acyl substitution.

CH3CH2CH2CONH2 (W);

CH3CH2CH2COCl (X);

CH3CH2CH2COOCH2CH2CH3 (Y);

(CH3CH2CO)2O (Z)

Back 34

W < Y < Z < X

Front 35

Rank the following three compounds in the order of increasing basicity.

Back 35

b < a < c

Front 36

What reagent(s) is/are needed to convert 1−ethylcyclohexene into1,2−dibromo−1−ethylcyclohexane?

A. H2, Pd−C

B. HBr, ROOR

C. HBr

D. Br2

Back 36

D. Br2

Front 37

Match 1H NMR spectra with compounds.

Back 37

C. Spectrum E is from compound X, and spectrum F is from compound Z.

Front 38

Which of the following compounds are aromatic?

Back 38

Compounds S, T, U, V, X, Z only.

Front 39

Which labeledH atom is most acidic? Which labeled H atom is least acidic?

Back 39

Hb is most acidic because its conjugate base is aromatic;

Hc is least acidic because its conjugate base isantiaromatic.

Front 40

Explain why 2,2,5,5−tetramethyl−3−hexyne can't be made using acetylide anions. Selectthe single best answer.

A. The 1° alkyl halide is too crowded for nucleophilic substitution.

B. It has an internal alkyne; and internal alkynes cannot be made using acetylide anions.

C. The 2° alkyl halide is too crowded for nucleophilic substitution.

D. The 3° alkyl halide is too crowded for nucleophilic substitution.

Back 40

D. The 3° alkyl halide is too crowded for nucleophilic substitution.

Front 41

Which is it

Back 41

X

Front 42

Assign carbon-13 NMR signals to each carbon in the compound shown.

Back 42

C1, C2, C3 and C4 appear at 23, 70, 32 and 10 ppm, respectively.

Front 43

Provide reagents for the following multistep synthesis.

Back 43

Reagent X is Cl2 and water; reagent Y is NaH; reagent Z is first NaC≡CH, then water.

Front 44

Using the pKa values given, which of the following bases are strong enough to deprotonate CH3COOH(pKa = 4.8)?

Back 44

Only bases V, Z and X are strong enough.

Front 45

Identify the reactants required for the formation of an enamine.

A) A ketone or an aldehyde and a secondary amine

B) A ketone or an aldehyde and a primary amine

C) An ylide and a primary amine

D) An ylide and a secondary amine

Back 45

A) A ketone or an aldehyde and a secondary amine

Front 46

What 10-carbon compound will undergo ozonolysis to give 2,4-pentadione as the only product?

A) 1,2-Dimethylcyclopropene

B) 1,6-Cyclodecadiene

C) 1,2,4,5-Tetramethyl-1,4-cyclohexadiene

D) 2,4-Dimethyl-1,4-cyclooctadiene

Back 46

C) 1,2,4,5-Tetramethyl-1,4-cyclohexadiene

Front 47

Which reagent would be used to reduce the alkene in cyclopentenone?

A) NaBH4

B) LiAlH4

C) 1 equivalent H2 and catalytic amount of Pd/C

D) DIBAL-H

Back 47

C) 1 equivalent H2 and catalytic amount of Pd/C

Front 48

Which of the following molecules would give an IR spectrum with the following peaks: 1650 cm-1; 2900 cm-1; 3040 cm-1; 3300 cm-1 (weak); 3400 cm-1 (weak)

Back 48

Compound Y

Front 49

Identify the hemiacetal carbon atom in this structure.

Back 49

B

Front 50

An unknown compound X has the molecular formula C6H14O. X shows a strong peak in its IR spectrum at3000 cm–1. The 1H NMR spectral data of X are given below. What is the most likely structure of X?

Back 50

Compound C

Front 51

Which of the following alkenes undergo allylic bromination to form a single monobrominated product (notincluding stereoisomers)?

Back 51

A

Front 52

Which of the following compounds give one singlet in 1H NMR spectra?

Back 52

Compounds S, U, W, Z

Front 53

Which of the following compounds matches or match the IR spectrum shown?

Back 53

X

Front 54

What is the first step in the general mechanism for electrophilic aromatic substitution?

A) Protonation of the aromatic ring

B) Deprotonation of the aromatic ring

C) Addition of the electrophile to the aromatic ring

D) Loss of the electrophile from the aromatic ring

Back 54

C) Addition of the electrophile to the aromatic ring

Front 55

Why is the nitro group a meta director?

A) Because it is sterically very large

B) Because it adds electron density to the meta position, thus activating it

C) Because it stabilizes the intermediate cation

D) Because it removes more electron density from the ortho and para positions than the meta position, thusdeactivating the meta position less

Back 55

D) Because it removes more electron density from the ortho and para positions than the meta position, thus deactivating the meta position less

Front 56

How could you separate the following compounds?

Back 56

Make a weakly basic aqueous solution, then extract with an organic solvent

Front 57

Rank the following from most to least acidic.

Back 57

Compound B > Compound C > Compound A

Front 58

What is the missing reagent in the reaction below?

Back 58

(Picture 30)

Compound B

Front 59

What is the product of the following reaction?

Back 59

Compound D

Front 60

Which reagent would bring about the following transformation?

A) LiAlH4

C) Br2, light

B) FeCl3

D) Basic KMnO4

Back 60

D) Basic KMnO4

Front 61

What reagent(s) is (are) needed to add NO2 to benzene?

A) HNO3, HCl

B) HNO3, H2SO4

C) NO2(g)

D) NO2, CCl4

Back 61

B) HNO3, H2SO4

Front 62

An electron donating group attached to a benzoic acid will:

A) Make the benzoic acid less acidic

B) Make the benzoic acid more acidic

C) Deactivate the benzene ring

D) Not change the acidity of the benzoic acid

Back 62

A) Make the benzoic acid less acidic

Front 63

Which of the reagents are suitable for the following transformations?

A. (1) SOCl2; (2) benzylamine (PhCH2NH2)

B. Benzylamine, DCC (N,N′-dicyclohexylcarbodiimide)

C. (1) Benzylamine; (2) heat to more than 100 °C

D. All above

Back 63

D. All above

Front 64

For proton and carbon NMR spectra, which statement is NOT correct?

A. Downfield direction is the direction from right to left in the spectra or from lower chemical shift to higherchemical shift

B. More deshielded nucleus will have a larger chemical shift than less deshielded nucleus

C. Normally, hydrogen on a tertiary carbon has a larger chemical shift than that on a primary carbon

D. Hydrogens on benzene ring are deshielded due to the current from circulating π electrons, the same is truefor alkenes and alkynes

Back 64

D. Hydrogens on benzene ring are deshielded due to the current from circulating π electrons, the same is true for alkenes and alkynes

Front 65

Rank the following enolates according to their stability from most stable to least stable.

Back 65

(pic 34)

X > W > Y > Z

Front 66

Select the appropriate reagents for the following transformation.

A. (1) DIBAL-H; (2) water

B. (1) LiAlH4; (2) water

C. (2) NaBH4; (2) water

D. All above

Back 66

(pic 35)

A. (1) DIBAL-H; (2) water

Front 67

What are the products of the following two reactions?

Back 67

Product U is Z; product V is W

Front 68

For molecular orbital (MO) theory, which of the following is NOT correct?

A. An MO that has more nodes is higher in energy than an MO that has fewer nodes

B. HOMO has higher energy than LUMO

C. The lowest energy MO formed by the six p atomic orbitals in benzene is the MO in which all the p orbitalsare in phase

D. The energy is not lowered when atomic orbitals form MOs

Back 68

B. HOMO has higher energy than LUMO

Front 69

What is the product of the following multiple step reaction?

Back 69

Compound Z