91Ó°ÊÓ

E1 elimination also known as unimolecular elimination, involves two steps—ionization and deprotonation. During ionization, carbocation intermediate is formed; and in deprotonation, a proton is lost by a carbocation. This happens in presence of base, which leads to formation of pi-bond in the molecule. In part (a), the given reactant undergoes E1 mechanism and forms Zaitsev product as major product. The carbocation formed in this E1 reaction is tertiary and will not rearrange.

Products obtained from E1 mechanism

E1 elimination also known as unimolecular elimination, involves two steps—ionization and deprotonation. During ionization, carbocation intermediate is formed; and, in deprotonation, a proton is lost by a carbocation. This happens in presence of base, which leads to formation of pi-bond in the molecule.

In part (b), the given reactant undergoes E1 elimination, and the carbocation produced in this reaction is secondary, and can either eliminate to give first two alkenes, or can rearrange by hydride shift to tertiary carbocation which produces last two products. Last two products are trisubstituted, but first product will certainly be the least.

Formation of products from E1 elimination of (1-bromoethyl)cyclohexane

The given reactant undergoes E1 elimination and the carbocation produced is secondary, and can either eliminate to give first alkene or can rearrange by methyl shift to give tertiary carbocation, which would produce last two products. The middle product is major as it is tetrasubstituted, versus disubstituted for last structure, and monosubstituted for first structure.

Formation of products from E1 elimination of given reactant