Chapter 11' Reactions of Alcohols

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Chapter 11. Reactions of Alcohols
A. Oxidation
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1. secondary alcohols
2. primary alcohols
(aldehydes even oxidize in the air!)
KMnO4 does exactly the same reactions
practical example!!
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There are reagents which selectively
oxidize primary alcohols to aldehydes include
B. Formation of halides with HX 1. overall
reaction
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2. mechanism - protonation then substitution, ie
3. limitations a. eliminations from carbocation
intermediate
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b. rearrangements from carbocation intermediate
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C. Halide formation with PX3 1. overall reaction
2. mechanism (a partial one)
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D. Formation of halides with thionyl chloride 1.
overall reaction
2. mechanism (the first step is some kind
of substitution reaction)
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E. Formation of tosylates
Note common theme in all of these reactions!!!
Tosylates are synthetically important
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Uses of tosylates
F. Dehydration reactions 1. overall reaction

• The reaction as written is endothermic to get it
  to go we need to
• Distill the alkene from reaction mixture.
• Add a drying reagent to tie up the water, eg
  CaCl2.

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2. mechanism - normally E1
3. orientation - normally Saytzeff - most
substituted, most stable alkene is formed
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Rearrangements can occur!
A realated reaction is called the Pinacol
rearrangement
(Pinacol)
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mechanism
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G. Oxidation of diols recall that-
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H. Esterification reactions well see the
exact mechanisms for these reactions in the
next semester - but they are easy - try them!
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Read pages 480 - 484 VERY CAREFULLY AT LEAST
FIVE TIMES
(on working reaction mechanisms)
Read pages 489 - 492 VERY CAREFULLY AT LEAST
SEVEN TIMES
(on doing multi-step synthesis)
SKIP CHAPTER 11.13 - esters of inorganic acids!!!
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I. Summary 1. Oxidation with Na2CrO7/ H2SO4 and
KMnO4/ H2O and PCC 2. Formation of halides with
HX 3. Formation of halides with PX3 4. Formation
of halides with thionyl chloride 5. Tosylate
formation and uses of tosylates 6. Dehydration of
alcohols 7. Rearrangements with carbocations -
the Pinacol rearrangement 8. Oxidation of diols
with HIO4 9. Esterification reactions - carbylic
acids and acid chlorides 10. Techniques in
multistep synthesis 11. How to figure out
reaction mechanisms