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Oxidation reactions result in...
- an increase in # of C-Z bonds
- a decrease in # of C-H bonds
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reduction reactions result in...
- decrease in # of C-Z bonds
- increase in # of C-H bonds
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R-CH=CH-R (alkene) + H2 & Pd/C →
- alkane
- called: "hydrogenation of alkene"
- syn addition of H's occur
- less stable alkene reacts faster
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How can you reduce an alkene to an alkane?
H2 & Pd/C
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R-CΞC-R (alkyne) + H2 & Pd/C →
alkane
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R-CΞC-R (alkyne) + H2 & Lindlar catalyst →
- cis alkene
- syn addition of H2 occurs
- reaction stops after one equivalent
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R-CΞC-R (alkyne) + Na & NH3 (L) →
- trans alkene
- called: "dissolving metal reduction on alkyne"
- anti addition of H2 occurs
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ketone + H2 & Pd/C →
2° alcohol
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aldehyde + H2 & Pd/C →
1° alcohol
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What are the only two reactions involving acetylide anion that we learned?
acetylide anion + R-X → extended C chain
acetylide anion + epoxide → opens epoxide, extends chain
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Reduction:
1° R-X + _______ → R (removes X)
mech?
regiochemistry?
- 1) LiAlH4 (LAH) Lithium aluminum hydride
- 2) H2O
- SN2
- backside attack
-
epoxide + _______ → opens epoxide
regio/stereo chemistry?
mechanism?
- 1) LiAlH4 (LAH) Lithium aluminum hydride
- 2) H2O
- backside attach at less subst. C
- SN2
-
what does LAH do?
- opens epoxides
- reduces alkyl halides
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What is peroxy acid?
R-CO3H
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epoxidation
alkene --(mCPBA)--> epoxide
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dihydroxylation
how do you make an anti-diol?
alkene --(1) mCPBA, 2)NaOH, H2O)--> anti-diol
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syn dihydroxylation
alkene --(1) OsO4, 2)NaHSO3, H2O)--> syn-diol
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Ozonolysis on internal alkene
- alkene --(1)O3 2)Zn, H2O |or| CH3SCH3)-->
- ketone & aldehyde or
- 2 ketones or
- 2 aldehydes
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Ozonolysis on internal alkyne
alkyne --(1)O3 2)H2O)--> 2 carboxylic acids
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Ozonolysis on terminal alkyne
alkyne + 1)O3 2) H2O --> carboxylic acid + CO2
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ozonolysis on terminal alkene
alkene + 1) O3 2) CH3SCH3 --> aldehyde + formaldehyde
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primary alcohol + PCC -->
aldehyde
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secondary alcohol + PCC -->
ketone
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primary alcohol + CrO3, H2SO4, H2O -->
carboxylic acid
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secondary alcohol + CrO3, H2SO4, H2O -->
ketone
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alkene + KMnO4, H2O, -OH -->
syn-diol
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True/False
mCPBA is a peroxyacetic acid
true
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