Devise a synthesis of (Z)-3-octene using one of the starting materials and the r

Question

Devise a synthesis of (Z)-3-octene using one of the starting materials and the reagents below.

Starting Materials:
Drawings (1-6) in picture above

Reagents:
a) NaNH2 / NH3 (l)
b) NaOH / H2O
c) iodomethane
d) iodoethane
e) 1-bromopropane
f) 2-bromoporpane
g) 1-bromo-3-methylbutane
h) t-butylbromide
i) H2 / Pd on carbon
j) H2 / Lindlar catalyst
k) H2/ NH3 (l)
l) Na / NH3 (l)

Starting material = ___?___ (Select 1-6)

Order of reagents = ___?___ (i.e. a,b,c)

Explanation / Answer

1-hexene + Br2 --> 1,2-dibromohexane 1,2-dibromohexane + strong base (I recommend lithium diisopropylamine, Li-N-iPr2, abbreviated LDA) --> 1-bromo-1-hexene + another equivalent of LDA --> 1-hexyne. This is a double dehydrohalogenation reaction to form an alkene from a vicinal dibromide. Strong bases (e.g. LDA, NaH) will deprotonate a terminal alkyne. This anion can be alkylated with ethyl iodide. 1-hexyne + LDA + EtBr --> 3-octyne. Alkynes can be reduced to the cis-alkene with Lindlar's catalyst, which is Pd/C treated with inactivating "poisons" such as quinoline and barium sulfate. 3-octyne + H2 + Lindlar's catalyst --> cis-3-octene. you may also refer : http://www2.chemistry.msu.edu/faculty/reusch/VirtTxtJml/alhalrx4.htm

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