2-Bromo-2-methylbutane is treated with $(\mathrm{CH}{}_3){}_3\mathrm{COK}$ in $(\mathrm{CH}{}_3){}_3\mathrm{COH}$. The major alkene is

The very bulky tert-butoxide cannot easily reach the hindered internal CH2 hydrogens or the more crowded transition state leading to the trisubstituted alkene; it removes a hydrogen from a terminal CH3 instead. The major product is the less substituted 2-methylbut-1-ene (Hofmann), unlike with ethoxide, which gives mainly 2-methylbut-2-ene.