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Solutions to Problems Organometallics

Building Bridges to Knowledge

Photo of Old Faithful, Yellowstone National Park 1. Using benzene, methanol, and any other necessary inorganic

materials, suggest syntheses for the following compounds.

(a)

2

(b)

3

(c)

4

(d)

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2. Suggest syntheses for the following

(a) 3-methyl-1-pentyn-3-ol from 2-butanone and any other

necessary organic or inorganic materialand any other necessary organic and inorganic compounds.

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(b)

and any other necessary organic and inorganic compounds

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(c)

and any other necessary organic and inorganic compounds

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+ H2O 3. Suggest products for the following reactions.

(a)

9

(b)

(c)

10

(d)

(e)

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4. Suggest the major product for the reaction of t-butylmagnesium bromide with compound A followed by acid hydrolysis. What is the IUPAC name for this compound?

The major product is trans-(e,e)-1,4-di-t-buty-1-cyclohexanol 5. Predict the major product expected from reacting the following

compound with excess phenylmagnesium iodide followed by acid hydrolysis.

6. Compound I, C3H5Br, reacts with magnesium in dry ether to

form C3H5MgBr. Treating C3H5MgBr with formaldehyde followed by acidic hydrolysis produces C4H8O, compound II.

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When three moles of C4H8O are treated with phosphorous tribromide, three moles of C4H7Br, compound III, are formed. Treating C4H7Br with magnesium in dry ether, followed by treatment with p-ethoxybenzaldehyde, resulted in the production of C13H17OMgBr. Acid hydrolysis of C13H17OMgBr produces C13H17OH, compound IV.

Suggest structures for compounds I, II, III, and IV.

compound I

compound II

compound III

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compound IV 7. Ferrocene is readily oxidized to ferrocenium ion by hydroxyl

radicals or other kinds of free radicals. Consequently, ferrocene may serve as a therapeutic agent for treating cancer. The reaction for ferrocene as a chemical to treat cancer may be described by the following equation.

Suggest a synthesis for ferrocene from cyclopentadiene.

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8. Suggest the product with the appropriate stereochemistry

produced when (2S)-2-bromobutane reacts with lithium n-propylcuprate.

The Cory-House reaction works best when the lithium dialkylcuprate reagent reacts with a primary alkyl halide. The reaction works reasonably well for unhindered secondary alkyl halides. Therefore, keeping in mind that the mechanism of the Cory-House reaction has not yet been clearly elucidated, an assumption can be made that the reaction probably takes place by backside attack of the lithium dialkylcuprate reagent. If this assumption is correct, then the product would be (3R)-3-methylhexane.

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9. Suggest the major product expected for the following reaction.

compound I (cyclohexyl tosylate) Give a rational for your answer.

The major product would be the elimination product:

The reaction would proceed through an elimination bimolecular mechanism, because the tosyl group is an excellent leaving group, and the reaction involves a strong base.

or

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10. Suggest a synthesis for compound B from compound A.

compound B

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compound A

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11. Suggest syntheses that would lead to the major products for the following compounds from any necessary organic or inorganic reagents. 1-deuteriobutane from butane

2-deuteriobutane from butane

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2-deuterio-2-methylpropane from isobutene

1-deuterio--2-methylpropane from isobutene

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12. The name of the following compound

is pentacyclo[4.2.0.02.5 03,8.04,7]octane. Suggest an IUPAC name for the following compound:

pentacyclo[6.2.0.02.7 03,10.06,9]decane

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13. Suggest structures for the product or products obtained in the following sequence of reactions.

14. Consider the following reaction schemas: Suggest structures for A, B, C8H14O, the product of (b); C8H14, the product of (c).

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(a)

(b)

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(c)

C8H14