NEETChemistryHydrocarbons
When 2 -bromo- 2 -methylbutane is heated with alcoholic KOH , a major alkene is formed. Identify the IUPAC name of this major product and the rule that governs its formation.
Options
- A2 -Methylbut- 2 -ene and Zaitsev rule
- B2 -Methylbut- 1 -ene and Zaitsev rule
- C2 -Methylbut- 2 -ene and Markovnikov rule
- D2 -Methylbut- 1 -ene and Hofmann rule
Correct answer
A. 2 -Methylbut- 2 -ene and Zaitsev rule
Step-by-step solution
The reaction of 2 -bromo- 2 -methylbutane with alcoholic KOH is a dehydrohalogenation ( -elimination) reaction. The structure of 2 -bromo- 2 -methylbutane is CH ₃- C ( Br )( CH ₃)- CH ₂- CH ₃ . It has two different types of -hydrogens. Elimination of a proton from the terminal CH ₃ group yields 2 -methylbut- 1 -ene (a disubstituted alkene). Elimination of a proton from the internal CH ₂ group yields 2 -methylbut- 2 -ene (a trisubstituted alkene). According to Zaitsev's rule, the more substituted alkene is more stab