Dehydrohalogenation of 2-bromobutane in the presence of a strong base proceeds via which of the following mechanistic pathways? A) S_N1 B) S_N2 C) E1 D) E2 E) none of the above

Question

Quizplus · Accepted Answer

Dehydrohalogenation of 2-bromobutane in the presence of a strong base occurs via an elimination mechanism. The two possible elimination mechanisms are E1 and E2. The E1 mechanism involves a carbocation intermediate formation and is favored in polar protic solvents with bulky leaving groups. The E2 mechanism occurs in a single step and is favored in aprotic solvents with relatively small or non-bulky leaving groups. Since 2-bromobutane is a primary halide, it will undergo E2 elimination in the presence of a strong base like ethoxide ion (C2H5O-), and hence the correct answer is D.

Dehydrohalogenation of 2-Bromobutane in the Presence of a Strong Base