Question

Which statement is true about the generation of an alkyne via elimination reactions?

a. The leaving group is in an allylic position.
b. When a strong base is used (NaH or NaNH2), high temperatures are required.
c. An acid workup is required when synthesizing a terminal alkyne.
d. The alkyne is generated through an E1 mechanism.
e. Only geminal dihalides can be used as a starting reagent.

Answer 1

b. When a strong base is used (NaH or NaNH2), high temperatures are required.

Step-by-step explanation:

a. The leaving group is in an allylic position. FALSE. The leaving group must be in a unsaturated position .

b. When a strong base is used (NaH or NaNH2), high temperatures are required. TRUE. In elimination reactions, high temperatures are necessaries to decrease the substitution products.

c. An acid workup is required when synthesizing a terminal alkyne. FALSE. When synthesizing a terminal alkyne it is necessary a workup because it is produced an alkynyl anion but is not necessary an acid workup, usually just with water the alkyne will be protonated.

d. The alkyne is generated through an E1 mechanism. FALSE. The mechanism of this reaction is E2 because there are a strong base and a good leaving group.

e. Only geminal dihalides can be used as a starting reagent. FALSE. Vicinal dihalides, vinyl halides and other several compounds could be used as starting reagents.

I hope it helps!