Title: Alkyne
1Chapter 8
2Properties
- CnH2n-2
- Reactions of alkyne that are common to alkene are
additions and oxidations. - Reactions that are specific to alkyne involve
acidity of ? C ? H (acetylenic) hydrogen. - sp hybridization - linear.
3Alkyne
- Naming
- Synthesis
- Reactions
4Naming
2,5-Dimethyl-3-hexyne
5Naming
3,3-Dimethyl-1-butyne
6Naming
3,3-Dimethyl-4-Octyne
7Naming
2,5,5-Trimethyl-3-heptyne
8Naming
2,4-octadien-6-yne
9Naming
6-Isopropylcyclodecyne
10Naming
3-Chloro-1-propyne
5-Hexyne-1-ol
3-butyn-2-ol
11Alkyne
- Naming
- Synthesis
- Reactions
12Alkyne Synthesis
Dehydrohalogenation of halides
Halogenation of alkene
Halogenation/dehydrohalogenation
13Alkyne Synthesis
vinylic halides
14Alkyne
- Naming
- Synthesis
- Reactions
15Reactions
- Addition of HX and X2
- Hydration - mercuration and hydroboration
- Reduction
- Oxidation
- Alkylation
16Bond Energies
Alkyne reactions are similar to alkenes - center
around the pi bond.
17Addition of HX and X2
Follow Markovnikovs rule trans addition.
18Reactions
- Addition of HX and X2
- Hydration - mercuration and hydroboration
- Reduction
- Oxidation
- Alkylation
19Mercuration
Oxymercuration
alkene
alcohol
enol
alkyne
vinyl alcohol
keto
tautomerism
isomerization
20Resonance stabilized intermediate
enol
keto
21Note!
22Mercuration
23Answer Key
24Mercuration
25Answer Key
26Mercuration Summary
- Alkyne ? Ketone.
- Tautomerism enol ? keto.
- Follow Markovnikov rule.
- Acid catalyzed.
27Reactions
- Addition of HX and X2
- Hydration - mercuration and hydroboration
- Reduction
- Oxidation
- Alkylation
28Hydroboration
alkene
alcohol
29enol
keto
Resonance stabilized intermediate
30Acid
enol is protonated first then loses a proton.
Base
enol loses a proton then regains it.
31Hydroboration
32Answer Key
33Hydroboration Summary
- Alkyne ? Ketone (internal ?) or aldehyde
(terminal ?). - Tautomerism enol ? keto.
- Follow non-Markovnikov rule.
- Base catalyzed.
34Hydroboration - Mercuration
35Answer Key
36Reactions
- Addition of HX and X2
- Hydration - mercuration and hydroboration
- Reduction
- Oxidation
- Alkylation
37Reduction
alkene
alkane
38Reduction
39Answer Key
40Reactions
- Addition of HX and X2
- Hydration - mercuration and hydroboration
- Reduction
- Oxidation
- Alkylation
41Oxidation
aldehyde
alkene
acid
42Oxidation
43Answer Key
44Oxidation Summary
- Alkyne ? caboxylic acid and CO2.
- Shortening the chain.
45Reactions
- Addition of HX and X2
- Hydration - mercuration and hydroboration
- Reduction
- Oxidation
- Alkylation
46Alkylation
deprotonated
acetylide anion
sodium amide
carbanion
powerful nucleophile
acidic
reaction center
47Alkylation
48Alkylation
49Answer Key
50(No Transcript)
51Alkylation Summary
- Alkyne (shorter) ? Alkyne (longer).
- Limited to primary alkyl bromides and iodides.
52Reactions
- Addition of HX and X2
- Hydration - mercuration and hydroboration
- Reduction
- Oxidation
- Alkylation
53Alkyne
54How would you carry out the following reactions?
55How would you synthesize the following products
from the given starting material?