Alkene Reactions - I

For each of the reactions on the left, predict the major organic product. Pay particular attention to the regiochemistry of the reaction and the possibility of carbocation rearrangement.

Click the mouse on the reactant molecule to view the answer;

click on the reagent to review the mechanism and regiochemistry of the reaction.

The addition of HCl to an alkene proceeds through a carbocation intermediate and results in the formation of an alkyl chloride with the chlorine bonded to the alkene carbon which would form the most stable carbocation (Markovnikov addition). Rearrangements are commonly observed.































The addition of HBr to an alkene in the presence of peroxides proceeds through a radical intermediate and results in the formation of an alkyl bromide with the bromine bonded adjacent to the alkene carbon which would form the most stable radical (anti-Markovnikov addition, overall).  Rearrangements are not observed.
 





































The addition of Br2 to an alkene proceeds through a bromonium ion intermediate and results in the formation of a trans-1,2 dibromide.
 





































The addition of HCl to an alkene proceeds through a carbocation intermediate and results in the formation of an alkyl chloride with the chlorine bonded to the alkene carbon which would form the most stable carbocation (Markovnikov addition).  Rearrangements are commonly observed.




































The addition of HCl to an alkene proceeds through a carbocation intermediate and results in the formation of an alkyl chloride with the chlorine bonded to the alkene carbon which would form the most stable carbocation (Markovnikov addition).  Rearrangements are commonly observed.




































The addition of HBr to an alkene in the presence of peroxides proceeds through a radical intermediate and results in the formation of an alkyl bromide with the bromine bonded adjacent to the alkene carbon which would form the most stable radical (anti-Markovnikov addition, overall).  Rearrangements are not observed.
 



































The addition of Br2 to an alkene proceeds through a bromonium ion intermediate and results in the formation of a trans-1,2 dibromide.
 



































The addition of HCl to an alkene proceeds through a carbocation intermediate and results in the formation of an alkyl chloride with the chlorine bonded to the alkene carbon which would form the most stable carbocation (Markovnikov addition).  Rearrangements are commonly observed.