The halide shown is treated with potassium tert-butoxide in tert-butanol. Which structure is the major alkene?

The compound is 2-bromo-2-methylbutane. The very bulky tert-butoxide removes a hydrogen from the sterically accessible methyl group rather than the more crowded CH2 group, so the Hofmann product 2-methylbut-1-ene is the major alkene (about 70 percent). With ethoxide the Saytzeff product would dominate.