Electrophilic Addition to Alkenes

1
Electrophilic Addition to Alkenes
Electrophile - chemical species that is electron
deficient
electron loving
The hydrogen cation(H) is one of the best
electrophiles - just a proton
This is major product
electrophilic addition to alkenes is an example
of a reaction that is regiospecific - given a
choice of regions in a molecule, the atoms add
specifically and predictably to certain positions
This product is not Formed
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Mechanism of Electrophilic Addition to Alkenes
The pathway that proceeds through the more stable
carbocation is preferred - This explains the
formation of the Markovnikov Product. Markovnik
ov Addition-The more electronegative atom adds to
the more substituted carbon in alkene addition
reactions.
Pathway 1
Pathway 2
2 carbocation
1 carbocation
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Energetic Changes in Electrophilic Addition
1 carbocation
2 carbocation
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Stereochemical Consideration with Addition
Reactions
This could be Top or Bottom Attack of Nucleophile
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Likely Pathways (Mechanisms) for Alkanes with
Leaving Groups Reacting with Nucleophiles
Strong Bases
Weak Bases
Leaving Groups
H2O, ROH, PR3, NH3, I-, Br-, Cl-, RS-, NC-, RCOO-
HO-, RO-, H2N-, R2N-
H2O, ROH, RCOO- (carboxylate), RSO3- (sulfonate),
RSO4- (sulfate), RPO4-2 (phosphate)
I-, Br-, Cl-,
Weak Nü
Strong Nü
Good Nü
This table will be provided on a quiz