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26 Cards in this Set
- Front
- Back
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Alkynes |
Triple bonds |
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Nomenclature rules |
change "ane" "yne" Follows same rules as alkenes 1st (double or triple) bond to show up |
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Name this compound |
hex-4-ene-1-yne |
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Naming priority |
alcohol>alkene>halide=alkane |
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pKa strengths of alkenes, alkanes, alkynes
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Alkane 62 Alkene: 45 Alkyne: 26 |
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Fundamental function of an acid |
Gives up protons (H+) electrons stay behind |
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Alkyne reaction |
Using NaNH2 (NR2-) with an alkyne protonates the hydrogen. Turns it into a good nucelophile used for E2 SN2 |
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E2 occurs with what type of CC? |
2, 3 carbon LG |
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SN2 |
Methyl, 1 carbon LG
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Preparation of alkynes uses what mechanism? |
E2 |
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Vicinal dihalide geminal dihalide and function |
Used in preparation of alkynes. |
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small base reaction forms triple bond on the ____ |
most substituted alkyne |
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Large bases at low temp (LDA -78C), causes the alkyne to form on the ______ |
less substituted carbon |
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Adding H2O at the end of the reaction serves what purpose? |
To quench the reaction, adds a hydrogen to the terminal alkyne. |
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Using hydrohalic acids |
adds to give most stable c.c. |
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Stereochemistry of adding hydrohalic acids |
racemic mixture |
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Review for LDA at low temperature |
LDA at low temperature adds double bond to the less substituted carbon |
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Acid catalyzed reactions |
Strong base, cation and strong acid, dissolves double bond and base adds to the most substituted carbon |
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Hydroboration oxidation |
2 step reaction involving BH3 in THF and a second step involving a strong, small base in hydrogen peroxide ANTI-Markonikov |
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Syn-addition |
adds to the same face simultaneously, hydroboration is an example of this. No carbocation rearrangement |
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Addition halogens to alkenes |
X^2: adds to either side of the double bond. Halogens must be anti |
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Br2 with a base (strong or weak) |
OH or base moves to the most substituted carbon |
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Reagent for epoxidation reactions |
mCPBA (peroxy acid) |
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Ozonolysis |
O3/Me2S or O3/H2O/Zn Also breaks a cyclic compound |
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Vicinal dihalide |
H H R-C-C-R X X |
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Geminal dihalide |
X H R-C-C-R X H |
