Question

What will result from the reaction between `(H_3C)_3C-Br` and `"sodium acetylide"`?

Answer 1

`"Isobutylene"`, and `"acetylene.........."`

Explanation:

You have the alkyl halide, `""_3(H_3C)C-Br` as the electrophile.

The nucleophile is the powerful base `"sodium acetylide"`: `Na^(+)""^(-):C-=CH`.

There are TWO possible reaction outcomes: (i) that the acetylide behaves as a nucleophile, and `C-C` bond formation occurs to give `"_3(H_3C)C-C-=CH` as the organic product, and sodium bromide as the inorganic product. Alternatively (ii), acetylide behaves as a base, and eliminates a proton from `"tert-butyl bromide"` to give sodium bromide (again, this product is a so-called thermodynamic sink), and `"isobutylene"`, `H_2C=C(CH_3)_2`.

Which product occurs? Got me? A priori, we would expect both reactions to occur to some extent; maybe conditions can be tweaked to favour one product over t'other; maybe the nucleophilic substitution product is disfavoured given the shrubbery around `C-Br`. The actual yields are the province of experiment.