Exam 1,2 orgo 2

The protons marked Ha and Hb in the molecule below are

diastereotopic

Describe the number of signals and their splitting in the 1H NMR spectrum of (CH3)2CHOCH3

3 signals: a singlet, a doublet, and a septet

What 1H NMR spectral data

2.6(1H, septet), 2.1(3H,s), 1.0(6H,d)

Which pair of reagents would produce the highest yield of (R)-2-ethoxybutane?

sodium(R)-2-butoxide + iodoethane

When cyclohexene is subjected to mercuration in methanol and the resulting mixture isreduced with sodium borohydride, the major organic product is

methoxycyclohexane

Which of the following reactions is classified as a Williamson ether synthesis?

Hg(OAc)2/CH3OH , NaBH4

What are the expected products of the reaction of PhOCH3 with concentrated HI?

phenol and iodomethane

Di-n-pentyl ether can be converted to 1-bromopentane by treatment with HBr through essentially a(n) __________ mechanism.

SN2

What descriptive term is applied to the type of diene represented by 2,4-hexadiene?

conjugated diene

In 1,3,5-hexatriene, there are ___ nodes in the HOMO and __ nodes in the LUMO for this molecule

2:3

How many nodes, other than the node coincident with the molecular plane, are found in thehighest energy π MO of 1,3 butadiene?

3

Which of the following represents the highest occupied molecular orbital for the conjugated pi system in Vitamin D3

3 nodes, 2 up, 2 down, 2 up

The structure of cholesterol is shown below. How many allylic carbons are there in this structure?

3

When trans-hex-3-ene is treated with PhCO3H, the major organic product is:

a 1:1 mixture of enantiomeric epoxides

Lasalocid A (shown below) is an antibacterial agent and a coccidiostat, which is producedby strains of Streptomyces lasaliensis. It is the drug in the feed additives. How many etherfunctional groups are present in Lasalocid A?

2

What compound is formed when ethylene oxide is reacted with n-pentyllithium followed bytreatment with aqueous acid?

1-heptanol

Which sequence correctly ranks the following dienes in order of increasing reactivity in theDiels-Alder reaction

3 < 2 < 1

When the relative energies of the s-cis and s-trans conformers of 1,3-butadiene arecompared, one finds that

the s-trans conformer is lower in energy than the s-cis

The number of pi molecular orbitals in a molecule is always equal to the number of

p orbitals used to construct the pi bonds

Predict the addition products of the following Diels-Alder Reactions

1,4 products I and III ; 1,2 product II

Which of the following molecules would you expect to be aromatic?

4,5,6,9

Which of the hydrogen atoms shown below is more acidic?

2

4) Which of the following compounds will undergo bromination most rapidly using Br2, FeBr3?

p-methylacetanilide

Which of the labeled H atoms (1 -5) in the following molecule would be predicted to be the most acidic?

1

Which of the following is also an acceptable name for 3-nitrophenol?

m-nitrophenol

Under what reaction conditions does the electrophilic chlorination of aromatic compounds usually occur?

Cl2, AlCl3

Which of the following species is attacked by benzene in the electrophilic nitration reaction?

NO2+

In electrophilic aromatic substitution reactions, a -NHCOCH3 substituent on the aromatic ring is

an activator and an o,p-director

Which of the following compounds will undergo Friedel-Crafts alkylation with (CH3)3CCl, AlCl3 most rapidly?

toluene

In electrophilic aromatic substitution reactions the hydroxyl group is an o,p-director because

it donates electron density to the ring by resonance and stabilizes the ortho and para sigma complexes

In electrophilic aromatic substitution reactions, a phenyl substituent on the aromatic ring is

an activator and an o,p-director

Which of the following is an intermediate in the bromination of toluene?

B

Which sequence correctly ranks the following aromatic rings in order of increasing rate of reactivity in an electrophilic aromatic substitution reaction?

2<1<3

Derivatives of the compound shown below are currently being examined for their effectiveness in treating drug addiction and metabolic syndrome (J. Med. Chem. 2006, 872). Which sequence ranks the following aromatic rings of this compound in order of increasing reactivity in an electrophilic aromatic substitution reaction (slowest to fastest reacting)

2<1<3

In electrophilic aromatic substitution reactions the nitro group is

a m-director since it destabilizes the meta sigma complex less than the ortho, para

In the addition of an electrophile to acetophenone, which of the following best describes the expected mode of reaction?

The o,p-positions are most deactivated to attack by the electrophile.

In electrophilic aromatic substitution reactions, a -CO2H substituent on the aromatic ring is

a deactivator and a m-director

In electrophilic aromatic substitution reactions, a cyano substituent on the aromatic ring is

a deactivator and a m-director