Alkyne Transformations — Virtual Textbook

Alkyne Reactions

Two isomeric alkyne starting materials are available for your use. They are:		A. 3-hexyne CH₃CH₂C≡CCH₂CH₃ B. 1-hexyne CH₃(CH₂)₃C≡CH

Using one or the other of these compounds, and selecting reagents from the list on the right, indicate how the following products might be prepared.
Each question (a. through h.) requires two responses. Under Starting Material enter A or B. Under Reagents enter a number corresponding to your selection.

Desired Product	Response Boxes
a. 3,3,4,4,tetrabromohexane CH₃CH₂CBr₂CBr₂CH₂CH₃	Starting Material Reagent Number
b. 3-hexanone CH₃(CH₂)₂COCH₂CH₃	Starting Material Reagent Number
c. propanoic acid CH₃CH₂CO₂H	Starting Material Reagent Number
d. hexanal CH₃(CH₂)₄CHO	Starting Material Reagent Number
e.cis-3-hexene cis-CH₃CH₂CH=CHCH₂CH₃	Starting Material Reagent Number
f. 2-hexanone CH₃CO(CH₂)₃CH₃	Starting Material Reagent Number
g. 2,2-dibromohexane CH₃CBr₂(CH₂)₃CH₃	Starting Material Reagent Number
h.trans-3-hexene trans-CH₃CH₂CH=CHCH₂CH₃	Starting Material Reagent Number

Reagents

1. H₂O + H₂SO₄ + HgSO₄

2. H₂ + Lindlar catalyst
(poisoned palladium)

3. NaBH₄ in ethyl alcohol

4. Disiamylborane [(C₅H₁₁)₂BH]
followed by H₂O₂ in base

5. Br₂ (2 equivalents)

6. KMnO₄ in H₂O
or ozone

7. HBr (2 equivalents)

8. Na in liquid ammonia (NH₃)

9. NaOH in aqueous ethanol

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