Question 1

What is the correct IUPAC name for the following compound?

$$\mathrm{CH_3CH=CHCH_2CH(CH_3$)_2}$$

Accepted Answer

5-methyl-2-hexene

Question 2

Which of the following is the correct structure for 2,3-dichloro-4-methylhexane?

Accepted Answer

A six-carbon chain with Cl on C2 and C3, and a methyl group on C4

Question 3

Upon radical monochlorination of methylcyclopropane, how many unique monochlorinated products are possible, and which (if any) are chiral?

Accepted Answer

Four products, two of which are chiral

Question 4

What is the product of the following reaction?

Cyclohexanol $$\xrightarrow{\mathrm{$$PBr_3$$,\ ether}}$$ ?

Accepted Answer

Bromocyclohexane

Question 5

In the following sequence, what is the role of NaBr in DMF when reacting with $$\mathrm{CH_3CH_2CH_2OTs}$$?

$$\mathrm{CH_3CH_2CH_2OTs + NaBr \xrightarrow{DMF}}$$

Accepted Answer

It acts as a nucleophile in an $$\mathrm{S_N2}$$ reaction, replacing the tosylate with Br

Question 6

Which of the following pairs of compounds have the same oxidation level?

1. $$\mathrm{CH_3CH_2OH}
2$$. $$\mathrm{CH_3CHO}
3$$. $$\mathrm{CH_3COOH}
4$$. $$\mathrm{CH_3CH_2CH_3}
5$$. $$\mathrm{CH_2$=CH_2$}$$

Accepted Answer

4 and 5

Question 7

Which of the following is a correct set of partners for a Suzuki–Miyaura cross-coupling to synthesize the following biaryl compound?

$$\mathrm{\begin{matrix} $$OCH_3$$ & & $$OCH_3$$ \ & 	ext{Biphenyl core} & \ $$OCH_3$$ & & $$OCH_3$$ \end{matrix}}$$

Accepted Answer

Aryl bromide and aryl boronic acid, each with $$\mathrm{$$OCH_3$$}$$ groups in the correct positions

Question 8

Predict the major product of the following elimination reaction:

$$\mathrm{(CH_3$)_3COH \xrightarrow{H_2SO_4}}$$

Accepted Answer

2-methylpropene

Question 9

Which of the following is the best nucleophile in polar aprotic solvents?

Accepted Answer

$$\mathrm{NH_2$^-}$$

Question 10

A $$^1H $$NMR absorption is observed at 436 Hz downfield from TMS on a 200 MHz spectrometer. What is the chemical shift in ppm?

Accepted Answer

$$2.18\ \mathrm{ppm}$$

Question 11

How many types of nonequivalent protons are present in methylcyclohexane ($$\mathrm{C_7H_{14}}$$)?

Accepted Answer

4

Question 12

Which of the following structures for $$\mathrm{C_4H_{10}}$$ would show only one peak in its $$^1H $$NMR spectrum?

Accepted Answer

isobutane (2-methylpropane)

Question 13

Which splitting pattern would you expect for the methyl protons in ethyl acetate ($$\mathrm{CH_3COOCH_2CH_3}$$)?

Accepted Answer

Triplet

Question 14

A compound with formula $$\mathrm{C_4H_{10}O}$$ shows the following $$^1H $$NMR data: $$0.95 (6H$$, doublet, $$J=7 Hz$$), $$2.10 (3H$$, singlet), $$2.43 (1H$$, multiplet). What is the most likely structure?

Accepted Answer

Isobutanol (2-methyl-1-propanol)

Question 15

Which of the following best explains how $$^1H $$NMR can distinguish between the two alkenes formed from acid-catalyzed dehydration of 1-methylcyclohexanol?

Accepted Answer

The chemical shift and integration of the vinylic protons will differ for each alkene

Question 16

In the E2 elimination of 2-bromobutane with potassium tert-butoxide in THF, what is the major product and why?

Accepted Answer

2-butene, because the base is bulky and favors the less substituted alkene (Hofmann product)

Question 17

Which of the following best describes the mechanism for the reaction of cyclohexyl iodide with KCN in DMSO?

Accepted Answer

$$\mathrm{S_N2}$$ nucleophilic substitution

Question 18

Which of the following statements about the nucleophilicity of $$\mathrm{NH_2$^-}$$ versus $$\mathrm{NH_3$} is $$correct?

Accepted Answer

$$\mathrm{NH_2$^-} is $$more nucleophilic because it has a negative charge and higher electron density

Question 19

Which of the following best explains why $$\mathrm{CH_3CO_2^-} is a $$weaker nucleophile than $$\mathrm{OH^-} in $$protic solvents?

Accepted Answer

$$\mathrm{CH_3CO_2^-} is $$resonance stabilized, making it less reactive

ORGO Exam 4 Practice Study Guide

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