Organic Chemistry Mechanism

Image's source: chemhelper

Electrophilic Addition

This mechanism takes place in alkenes.

Instructions: Follow the links (underlined sentences) below to understand the electrophilic addition mechanism.

Links:

1. What is electrophilic addition?

2. The reaction with bromine... (Addition of bromine to a carbon-carbon double bond).

     i. Explanation 

   ii. Reaction of unsymmetrical alkene with bromine (please refer to 3 (ii)(d)) below.

3. The reaction with hydrogen halide... (Addition of hydrogen bromide)

    i. Reation of symmetrical alkene: Explanation   and More detailed explanation.

   ii. Reaction of unsymmetrical alkene (Markovnikov addition)

       Eg.: The reaction between propene and hydrogen bromide in the gas phase:

CH₃CH=CH₂ + HBr → CH₃CH₂BrCH₃

   ii(a). Carbocations (carbonium ions) and their stability... (Essential pre-reading before you tackle anything else in this section.)

    ii(b). Why unsymmetric alkenes are a problem ... (Explains the reasons behind Markovnikov's Rule, and gives a general mechanism for these more awkward reactions. This is also essential reading before you look at specific reactions.)

   ii(c). Reaction between Propene and HBr (Explanation) More details.

   ii(d). Reaction between Propene and Bromine and More details.

4.  Movie on the mechanism (if you can't see the movie here, try click at the movie file below.)