Term
| halohydrin formation reaction in a lab |
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Definition
alkenes are insoluble in water, and Br2 is dangerous. Instead, we use:
- NBS as a Br donor
- DMSO as a solvent; it's polar, so water can then react |
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Term
| oxydization in organic chemistry |
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Definition
- decrease in electron density around carbon
- increase in bonds from carbon to an electronegative atom
- decrease in bonds from carbon to hydrogen |
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Term
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Definition
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Term
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Definition
| cyclic ether in a three-membered ring |
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Term
hydroboration/oxidation
vs.
oxymercuration/reduction |
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Definition
hydroboration: [image]
(non-Markovnikov)
oxymercuration:
[image]
(Markovnikov) |
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Term
| hydroxylation (oxidation) |
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Definition
[image]
note: SYN addition! |
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Term
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Definition
[image]
note: TRANS formed! |
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Term
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Definition
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Term
| how would one remove an OH from a cyclene and restore the double bond? |
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Definition
| H2SO4 and water in THF at high temperatures |
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Term
| how would one remove a halogen from an alkane and restore the double bond? |
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Definition
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Term
| cleave an alkene's double bond and NOT add an alcohol for every hydrogen |
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Definition
ozoneolysis - ozone, then Zn and H3O+
[image] |
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Term
| cleavage by potassium permanganate |
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Definition
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Term
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Definition
| tetrahydrofuran (a common solvent) |
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Term
| we don't do halohyration in the lab with normal Br2. Why? What do we use instead? |
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Definition
Br2 is very dangerous; also, alkenes are usually water insoluble.
our Br donor is NBS; our solvent (with water) is DMSO |
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Term
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Definition
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Term
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Definition
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Term
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Definition
- markovnikov
use: Hg(OAc)2 in aqueous THF (H2O/THF)
followed by NaBH4 |
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Term
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Definition
ANTI-markovnikov
BH3 in THF, followed by H2O2 and OH- in water |
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Term
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Definition
| acid catalyzed reaction with water to open the ring |
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Term
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Definition
cleaves in water/THF
- HIO4
- cleaves SINGLE bonds between two carbons with OH substituants and turns them into carbonyls |
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Term
| how would one hydrate an alkyne? |
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Definition
| with water and acid, catalyzed by HgSO4 |
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Term
| how do you stop reduction of an alkyne when it becomes an alkene? (hydrogenation) |
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Definition
using a lindlar catalyst indead of Pd/C (cis)
OR
using Li or Na with NH3 (trans) |
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Term
| KMnO4 or O3 cleavage of alkynes |
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Definition
internal alkyne: two carboxylic acids
terminal alkyne: one carboxylic acid and one CO2 |
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Term
| why is alkyne H more acidic than alkene and alkane? |
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Definition
because its conjugate base is more stable; this is because:
1. sp orbital has a greater proportion of "s character"
2. s orbital is closer to the nucleus and therefore lower energy
3. being a sphere stabilizes an s orbital |
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Term
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Definition
formed when H comes off a triple bond; eg:
HC=-C:- |
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Term
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Definition
| treating an alkyne with NaNH2 to deprotonate it; then applying it to a PRIMARY alkyl halide so that it replaces the halide (this does NOT work on secondary or tertiary alkyl halides!) |
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Term
| solvent used in the addition of halogens to an alkene (X2) and geometry of the final product |
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Definition
solvent: CH2Cl2
the two halogens will be trans to each other |
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Term
| how does one create a halohydrin? |
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Definition
| halogen gas in a solvent of water; will be in TRANS |
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Term
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Definition
| strong acid and water added to an alkene; markovnikov; the acid is regenerated in the end (it's a catalyst) |
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Term
| hydration to obtain markovnikov produce |
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Definition
oxymercuration!
- Hg(OAc)2 in water and THF
and then
- NaBH4 |
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Term
| what is the purpose of NaBH4 in oxymercuration? |
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Definition
| it supplies hydride (H-) and removes the HgOAc from the molecule |
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Term
| how do you dihydroxylate an alkene? |
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Definition
| OsO4 with pyridene followed by NaHSO3 in water |
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Term
| how does one cleave a 1,2 diol? |
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Definition
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Term
| after oxydation by potassium permanganate, what happens to a primary carbon? secondary? tertiary? |
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Definition
primary: CO2
secondary: carboxylic acid
tertiary: ketone |
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Term
| what is the difference between adding HX to an alkene and an alkyne? (solvent) |
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Definition
alkene - solvent is ether
alkyne - solvent is acetic acid |
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