Advices For Studying Organic Chemistry

R 3 B NaOH, 25 oC 3 R + Na 3 BO 3

oxidation

OH

H 2 O 2

3. The alkyl migration takes place with retention of configuration of the alkyl
   group which leads to the formation of a trialkyl borate, an ester, B(OR) 3.

1. The ester then undergoes basic hydrolysis to produce three molecules of alcohol
   and a borate ion.
   B(OR) 3 + 3 OH– H^2 O 3 R–OH + BO 3 3–

4. The net result of hydroboration-oxidation is an anti-Markovnikov addition of
   water to a double bond.


5. Two complementary orientations for the addition of water to a double bond:
   
   
   1. Acid-catalyzed hydration (or oxymercuration-demercuration) of 1-hexene:
   
   
   
   

CH 3 CH 2 CH 2 CH 2 CH CH 2

H 3 O+, H 2 O

OH

CH 3 CH 2 CH 2 CH 2 CHCH 3

1-Hexene 2-Hexanol

2) Hydroboration-oxidation of 1-hexene:

CH 3 CH 2 CH 2 CH 2 CH CH 2 1.THF:BH^3

1-Hexene 1-Hexanol (90%)

2. H 2 O 2 , OH− CH^3 CH^2 CH^2 CH^2 CH^2 CH^2 OH

3) Other examples of hydroboration-oxidation of alkenes:

C CHCH 3

CH 3

H 3 C H 3 C CCHCH 3

H

CH 3

OH

H 2 O 2 , OH−

2-Methyl-2-butene 3-Methyl-2-butanol (59%)

1. THF: H 3


2. 
   

B