Question 1
Select the expected
major product of the reaction sequence shown.
◦ 3-methylhexyne
◦ 2-bromo-3-methylhexyne
◦ 1-bromo-3-methylhexybe
◦ 3-methyl-1-hexyne
◦ 3-methyl-2-hexyne
Question 2
The most frequent method for preparing terminal alkynes using an elimination reaction involves dissolving sodium amide (NaNH
2) in liquid ammonia (NH
3). Which of the following statements offers the best explanation for the above statement?
◦ Steric hindrance favors preparation of the less substituted terminal alkyne.
◦ Sodium amide is required because it increases the stability of the terminal alkyne, stabilizing the intermediate.
◦ Sodium amide irreversibly deprotonates the terminal alkyne, driving the elimination reaction to completion.
◦ Sodium amide deprotonates internal alkynes, which begins the series of reactions necessary reactions to generate a terminal alkyne.
◦ This provides an environment in which terminal alkynes are more stable than the internal alkynes and therefore the favored product.
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