addition of h 2 o across a double bond. addition of h 2 o across a double bond occurs in three...
DESCRIPTION
Acid-Catalyzed Hydration OH - adds in a markovnikov fashion, attaching to the most substituted carbon. H + adds like in the addition of HX across a double bond.TRANSCRIPT
Addition of H2O across a Double Bond
Addition of H2O across a double bond Occurs in three different ways: Acid-Catalyzed Hydration Oxymercuration Hydroboration
Acid-Catalyzed HydrationCH3 CH3
CH3
+ OH2H2SO4 CH3 CH3
CH3
OH
• OH- adds in a markovnikov fashion, attaching to the most substituted carbon.
• H+ adds like in the addition of HX across a double bond.
Acid Catalyzed Hydration: Mechanism
CH3CH3
CH3
H2SO4 + OH2OH3
+ + HSO4-
O+
HH
H
CH3C
+CH3
CH3
H+ O H
H
Acid Catalyzed Hydration: Mechanism
CH3C
+CH3
CH3
OH H
CH3CH3
CH3
OH2+
CH3CH3
CH3
O+H
H
+ OH2 CH3CH3
CH3
OH
OxymercurationCH3 CH2
CH3
Hg(OAc)2+H2ONaBH4
CH3 CH3
CH3 OH
• No rearrangement occurs. OH- bonds to the most substituted carbon in the double bond.
• No rearrangement occurs because no carbocation forms.
Oxymercuration: Mechanism
CH3CH2
CH3
CH3
Hg+O
O
CH3
O HH
CH3
CH3 O+
HH
OO
CH3
O
OH CH3
Oxymercuration: Mechanism
CH3
CH3 OH
OO
CH3
NaBH4 CH3
CH3
CH3
OH
HydroborationCH3 CH3
CH2
CH3 CH3
OH
BH3
1. H2O2 2. OH-
• the OH- group bonds to the least substituted carbon in what is called “anti-markovnikov addition”
Hydroboration: Mechanism
What is the Product?
CH3
CH3
OH
CH3
CH3
CH3
OH
CH3
CH3
CH3
OH
CH3
CH3
CH2 BH3
NaOH, H2O2?
What is the Product?
CH3
CH3
CH2 H2SO4
OH2
CH3
CH3
OH
CH3
CH3
CH3
OH
CH3
CH3
CH3
OH
?
What is the Product?CH3
CH3
CH2Hg(OAc)2NaBH4, H2O
CH3
CH3
OH
CH3
CH3
CH3
OH
CH3
CH3
CH3
OH
?
