Respuesta :
The complete reaction along with intermediates is given below, with each step highlighted in different color.
Step 1:
In this step an acidic proton at alpha position is abstracted from lactone moiety and corresponding enolate is formed, which is resonance stabilized. Both structures are shown. In this case LDA (Lithium diisopropylamide) acts as a base.
Step 2:
The enolate formed attacks on Methyl Iodide, as Iodide being greater in size is a good leaving group and alpha methyl moiety is generated.
Step 3:
This step is acid catalyzed Bromination. Bromine is added at alpha position.
Step 4:
This is elimination reaction and is according to Hofmann's Rule. Here less substituted alkene is generated.
Step 1:
In this step an acidic proton at alpha position is abstracted from lactone moiety and corresponding enolate is formed, which is resonance stabilized. Both structures are shown. In this case LDA (Lithium diisopropylamide) acts as a base.
Step 2:
The enolate formed attacks on Methyl Iodide, as Iodide being greater in size is a good leaving group and alpha methyl moiety is generated.
Step 3:
This step is acid catalyzed Bromination. Bromine is added at alpha position.
Step 4:
This is elimination reaction and is according to Hofmann's Rule. Here less substituted alkene is generated.
