Question

What is the best set of conditions to convert an appropriate dihalide into a terminal alkyne?

a. 1 equivalent of nanh
b. 2 equivalents of naoh
c. 2 equivalents of nanh2
d. 3 equivalents of nanh2, then quench with h3o

Answer 1

The best condition for converting a dihalide into a terminal alkyne is using 3 equivalents of NaNH2, followed by quenching with H3O+.

Step-by-step explanation:

The best set of conditions to convert a dihalide into a terminal alkyne is to use 2 equivalents of sodium amide (NaNH2). This base is strong enough to remove two equivalents of hydrogen halide from a vicinal or geminal dihalide, leading to the formation of a terminal alkyne. The reaction is performed in a polar aprotic solvent such as liquid ammonia or ethylene diamine. Following the deprotonation steps, the reaction mixture is typically quenched with water or weak acid like dilute HCl to neutralize the remaining NaNH2 and recover the product. Therefore, the correct answer to the question is option (d) 3 equivalents of NaNH2, then quench with H3O+.