2-Bromo-2-methylbutane is heated with alcoholic $\mathrm{KOH}$ and the major alkene is subjected to reductive ozonolysis. The carbonyl compounds obtained are

E2 elimination follows Zaitsev's rule and gives the more substituted alkene, 2-methylbut-2-ene, $(\mathrm{CH}{}_3){}_2\mathrm{C}=\mathrm{CH}-\mathrm{CH}{}_3$. Cleavage of the C=C bond gives $(\mathrm{CH}{}_3){}_2\mathrm{C}=\mathrm{O}$ from one end and $\mathrm{CH}{}_3\mathrm{CHO}$ from the other. The products are propanone and ethanal. (The Hofmann alkene 2-methylbut-1-ene would have given butan-2-one and methanal.)