Alkynide Synthesis - Online Tutor, Practice Problems & Exam Prep

Why alkynide alkylation reaction shown below fails to yield the desired product? What actual major product would be formed in this reaction?

Why does the following S_N2 reaction of a 1° bromide by alkynide fail to give the desired product?

Determine the energy difference (in kJ/mol) between the least stable staggered conformer and the least stable eclipsed conformer for the compound given below.

1,2-dibromoethane

Note: A gauche conformer has two energy barriers, 22.6 kJ/mol and 39.7 kJ/mol. The anti conformer is 5.86 kJ/mol more stable than a gauche conformer.

Show the synthesis of non-4-yne by adding the butyl group and the propyl group afterward. Give all the reagents and intermediates.

Using acetylene as the starting material, show how each of the following compounds can be synthesized. In your synthesis, you can use any compounds with four or less carbon atoms.

(i) but-1-yne

(ii) but-2-yne

(iii) cis-but-2-ene

Using acetylene as the starting material, show how each of the following compounds can be synthesized. In your synthesis, you can use any compounds with four or less carbon atoms.
(i) trans-but-2-ene
(ii) 1,1-dibromobutane
(iii) 2,2-dibromobutane

Propose a reaction pathway showing how the following compound can be prepared starting with propyne.

Provide a reaction scheme for the synthesis of trans-non-4-ene using acetylene as the starting material.

Provide a reaction sequence showing how the following target molecule can be prepared from the starting material.

CH₃CH₂CH₂CH₂Cl → CH₃CH₂CH₂CH₂CH₂CH₂CH₃

Propose the synthesis of the following molecule starting with acetylene.

Determine how the following compound is synthesized using ethylene as the starting material.

Propose a synthesis of the given molecule from ethylene.

Draw the synthesis of (Z)-5,5-dimethyl-1-phenylhex-2-en-1-ol from benzaldehyde and other reagents.

Suggest a synthesis to convert pent-1-yne to cis-8-methylnon-4-ene.

Illustrate how the following compounds can be synthesized from acetylene and other necessary reagents.

The majority of alkene synthesis results in the formation of the more stable trans isomer. Provide a reaction scheme for synthesizing henicos-7-ene from acetylene and other compounds that specifically produce the cis isomer.

Show a sequence of steps to show how the target molecule can be prepared using the provided starting material.

Ignoring stereochemistry, give the structures of (i) through (iv).

Using acetylene, (2-bromoethyl)benzene, and any other reagents, propose a synthesis of the following alkene.

Determine how cis-3-heptene can be synthesized starting from butyne.

Show how the following synthetic transformation can be accomplished. Give the structures of all intermediates.
2,2-dibromobutane → but-1-yne