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 ProductResponse Boxes
a.   3,3,4,4,tetrabromohexane   CH3CH2CBr2CBr2CH2CH3Starting Material  
Reagent Number  
b.   3-hexanone   CH3(CH2)2COCH2CH3Starting Material  
Reagent Number  
c.   propanoic acid   CH3CH2CO2HStarting Material  
Reagent Number  
d.   hexanal   CH3(CH2)4CHOStarting Material  
Reagent Number  
e.   cis-3-hexene   cis-CH3CH2CH=CHCH2CH3Starting Material  
Reagent Number  
f.   2-hexanone   CH3CO(CH2)3CH3Starting Material  
Reagent Number  
g.   2,2-dibromohexane   CH3CBr2(CH2)3CH3Starting Material  
Reagent Number  
h.   trans-3-hexene   trans-CH3CH2CH=CHCH2CH3Starting 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

This script written by William Reusch, Dept. of Chemistry, Michigan State University. Please send comments and corrections to whreusch@pilot.msu.edu.