Using the reagents below, list in order (by letter, no period) those necessary to transform 1-chlorobutane into 1-butyne. Note:
Not all entry-fields provided may be needed. Choose "na" in any space where you have no reagent . a. H2, Pt:
b. H2, Lindlar's Catalyst
c. H2, Ni2B{P-2)
d. Br2, CCI4
e. NaNH2, Mineral oil, heat
f. NH4CI G.
g. t -BuOK, t -BuOH, heat
h. CH3 I
i. CH3CH2 I
We are attempting to synthesize 1-butyne from 1-chlorobutane. Since 1-chlorobutane is a primary alkyl halide, 1-butene is formed when 1-chlorobutane is reacted with a bulky base such as t -BuOK or t -BuOH in presence of strong heat. This is an E2 reaction.
Secondly, the 1-butene is reacted with bromine in carbon tetrachloride. The vicinal dihalide (1,2-dibromobutane) is formed. This can now undergo further elimination reactions in the presence of sodamide and strong heat to yield 1-butyne which is the desired product. These reactions involve the elimination of the first HBr molecule to give an alkenyl bromide. A second elimination now gives the terminal alkyne.
