Mechanism of Addition of HX to an Alkene
Propose a two-step mechanism for the addition of HI to methylenecyclohexane to give 1-iodo-1-methylcyclohexane.
Strategy
The mechanism for the addition of HI to an alkene is similar to the twostep mechanism proposed for the addition of HCl to 2-butene.
Step 1: Reaction of H1 with the carbon–carbon double bond forms a new C – H bond to the carbon bearing the greater number of hydrogens and gives a 3° carbocation intermediate.
Step 2: Reaction of the 3° carbocation intermediate with iodide ion completes the valence shell of carbon and gives the product.
