Electrophilic addition Start
Reagents
Reagents
HCl
HBr
Cl2
HI
H2O/H+
Br2
1 Halogen atom added
H adds first
H ends up on less substituted end.
Less stable
carbocation
NOT FORMED
More stable
carbocation
FORMED
Reaction intermediate has 3 possible structures
NEGLIGIBLE
Markovnikov product
MINOR
Negligible contributor is ignored.
Nucleophile attacks more substituted end
Nucleophile ends up on more
substituted end.
Halonium ion
MAJOR
Top face of intermediate is blocked by halogen atom.
·
·
2nd halogen atom
added to bottom
face (anti addition).
Halogen attacks
more stable
carbocation end.
Product
Mechanism Inspector is provided by The Royal Society of Chemistry and supported by Shire
© Royal Society of Chemistry 2011
Thomas Graham House (290), Science Park,
Milton Road, Cambridge, CB4 0WF
UK Charity No. 207890