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13 Cards in this Set
- Front
- Back
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Na(s), NH3(l) |
chemical reduction of an alkyne: anti-addition produces a trans double bond |
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X2 in excess |
4 equivalent X's add across the C-C bond |
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X2 (1eq) |
trans major pdf of X adding across C-C double bond |
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Lindlar cat., H2 |
reduce alkyne --> alkene via sun addition of H2 across a double bond = cis double bond |
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HX |
Hydrohalogenation 1 eq = makes trans product & X adds to most sub C xs = dihalide pdt (2X on same C) |
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1.BH3-THF 2.H2O2, NaOH |
H2O adds to triple bond to form aldehyde (internal alkynes) or ketone (terminal alkynes) (tautomerization) |
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1.O3 2.H2O |
Oxidative cleavage of sigma and pi bonds of alkyne Internal --> 2 carboxylic acids Terminal --> 1 carboxylic acid & 1 CO2 |
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H2, 3 atm, Pd |
reduces alkyne to alkane by adding H2 to triple bond (unfavorable b/c can't stop at alkene pdt) |
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Strong Base |
make double & triple bond small base --> internal big base --> external |
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1.NaH 2.CH3I (alkyl halide) |
deprotonate terminal alkyne & add RX via SN2 rxn |
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HgSO4, H2SO4, H2O |
Hg2+ catalyzed hydration of alkyne: produces ketone (tautomerization) |
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Na,NH3 |
alkyne --> alkene |
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Br2 or NBS, hv or light |
Allylic Bromination: products result from substitution of hydrogen by Br at the position next to a double bond (allylic) 1. Br2 undergoes hemolytic cleavage = 2 Br radicals 2. Br radical attacks allylic H from alkene = HBr byproduct and radical alkene molecule 3. Br radical and alkene radical combine = Br added to alkene |
