OCHEM EXAM 3

Which of the following alkenes is the major product when 2-bromo-2-methylpentane is treated with sodium ethoxide in ethanol?

(Z)-4-methylpent-2-ene

Using Zaitsev's rule, choose the most stable alkene among the following.

1-methylcyclohexene

Provide a series of steps through which 2-methylbutane is converted into 2-methylbut-1-ene?

1. Br2, hv2. (CH3)3CO-

Which of the following best approximates the CCC bond angle of propene?

120

How many moles of carbon dioxide are generated when one mole of the compound shown is treated with an excess of warm, concentrated KMnO4 solution?

3

Which of the alkyl chlorides listed below undergoes dehydrohalogenation in the presence of a strong base to give pent-2-ene as the only alkene product?

3-chloropentane

Which of the following molecular formulas corresponds to a monocyclic saturated compound?

3H7N

The prostaglandin precursor arachidonic acid has the molecular formula C20H32O2. Given that arachidonic acid is an acyclic carboxylic acid that contains no carbon-carbon triple bonds, how many carbon-carbon double bonds are present?

4

Provide the reagents necessary for carrying out the transformation of cyclopentane to cyclopentene.

Br2, HV, NaOH

Dehydrohalogenation of an alkyl halide by treating it with a strong base to yield an alkene product typically occurs by what reaction mechanism?

E2

Consider the constitutional isomers 2-methylbut-1-ene, 2-methylbut-2-ene, and 3-methylbut-1-ene. When each of these alkenes is subjected to catalytic hydrogenation (H2, Pt), a single product results. Which of the following best describes the structural relationship among these products?

The products are identical

Addition of Br2 to (EEE)-hex-3-ene produces ________.

a meso dibromide

Treatment of 2-methylpropene with which of the following reaction conditions results in an anti-Markovnikov addition product?

both "dry gaseous HBr with peroxides present" and "BH3-THF, followed by alkaline H2O2"

Which of the following intermediates is thought to occur in the mechanism by which alkenes are hydrated in the presence of acid?

carbo cation

Which of the following additions to alkenes occur(s) specifically in an syn fashion?

dihydroxylation using OsO4, H2O2, addition of H2, and hydroboration

Dehydrohalogenation of 2-bromobutane in the presence of a strong base proceeds via which of the following mechanistic pathways?

e2

When an alkene is subjected to treatment with Hg(OAc)2 in alcohol followed by reaction with NaBH4, what new class of compound is formed?

ether

Which of the following bases would most encourage the formation of Hofmann products in E2 eliminations?

iPr)2NH

Carbon-carbon single bonds tend to be ________ and ________ than carbon-carbon double bonds.

longer, weaker

Which of the following is the best reaction sequence to use if one wants to accomplish a Markovnikov addition of water to an alkene with minimal skeletal rearrangement?

oxymercuration-demercuration

The carbon-carbon bond length in ethylene is ________ than the carbon-carbon bond length in ethane, and the HCH bond angle in ethylene is ________ the HCH bond angle in ethane

shorter; larger than

Treatment of cyclopentene with peroxybenzoic acid ________.

yields a meso epoxide