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34 Cards in this Set
- Front
- Back
Substitution: SN2 (3) |
Concerted Process: LG leaves as nucleophile attacks Second Order: rate depends on both [reactants] Stereospecificity: back-side attack w/ walden inversion |
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Substitution: SN1 (4) |
Stepwise Process: LG leaves then nucleophile attacks carbocation First Order: rate dependent upon [substrate] Stereochemistry: carbocation attacked from either side --> inversion + retention of configuration Carbocation Rearrangement: low percentage of less stable arrangement |
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Reagent: TsCl/Pyridine (1) |
Conversion of OH to good leaving group for SN2 reactions |
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Bredt's rule (1) |
Bridgehead carbon of a bicyclic compound cannot possess a C=C double bond requiring a trans-pi bond in a ring of less than 8 carbons |
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Z designation for alkenes (1) |
Zussamen: same side (cis) |
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E designation for alkenes (1) |
Entgegen: opposite side (trans) |
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Elimation: E2 (5) |
Concerted mechanism: Base takes a proton and LG leaves simultaneously Second Order: rate depends on both [reactants] Regiochemistry: Zaitsev Product unless using bulky base --> Hofmann Product Stereoselectivity: 2 Hydrogens on beta position = cis + trans conformers (trans slightly lower E) Stereospecificity: 1 Hydrogen on beta position = anti-periplanar (Cyclohexane: LG & H are axial) |
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Elimination: E1 (6) |
Stepwise mechanism: LG leaves then Base takes proton First Order: rate depends on [substrate] Regiochemistry: Zaitsev regardless of base Stereoselectivity: preference for trans isomer Stereospecificity: none Carbocation Rearrangement: low percentage of less stable arrangement |
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H2SO4 Heat |
E1 reaction of secondary and tertiary alcohols More substituted alkene formed |
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Addition: Hydrohalogenation (H-X across alkene) (3) |
Regioselectivity: none if symmetrical unsymmetrical alkene --> Markovnikov addition * peroxides cause anti-Markovnikov addition Stereochemistry: Carbocation attack from either side --> new chirality center = racemic mixture of enantiomers Carbocation Rearrangement: low percentage of less stable arrangement |
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Addition: Acid-Catalyzed Hydration (3) |
Regioselectivity: Markovnikov addition Equilibrium [H2O]: Dilute acid = more alcohol Conc. acid = more alkene Stereochemistry: New chirality center = racemic mixture of products |
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Addition: Catalytic Hydrogenation (1) |
Stereospecificity: Syn addition 0 chirality centers = 1 product 1 chirality center = Pair of enantiomers 2 chirality centers = Pair of enantiomers (syn) Symmetrical alkene = meso compound |
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Addition: Oxymercuration-demercuration (2) |
Regioselectivity: Markovnikov addition w/out carbocation rearrangement Stereospecificity: OH & H are added anti |
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Addition: Hydoboration-oxidation (2) |
Regioselectivity: anti-Markovnikov Stereospecificity: Syn addition of H & OH producing enantiomers
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Addition: Halogenation (1) |
Regioselectivity: anti-addition of halogen *trans isomer may produce meso compound
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Addition: Halohydrin (1) |
Regioselectivity: anti-addition of a Halogen and H2O; H2O attacks more substituted carbon to stabilize intermediate partial charge |
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Addition: Anti-Dihidroxylation (1) |
Regioselectivity: Formation of epoxide anti-addition of two OH groups yields trans diol |
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Addition: Syn-Dihydroxylation (1) |
Regioselectivity: Syn addition of OH groups via formation of osmate ester |
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Addition: Oxidative Cleavage (3) |
Regioselectivity: none Stereoselectivity: none All C=C bonds cleaved to form pair of C=O bonds |
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Alkyne preperation: Alkyl dihalide (3) |
2 leaving groups + 2 successive E2 rxns geminal (2 halides, same carbon) vicinal (2 halides, adjacent carbons) Requires a very strong base H2O addition as a second step will reprotonate terminal alkynide ion |
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Reduction of Alkynes: Catalytic Hyrdrogenation (3) |
Alkyne consumes 2 equivalents of H2/Pt Poisoned catalyst - stops reaction at cis alkene Syn-addition prevents isolation of trans alkene |
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Reduction of Alkynes: Dissolving Metal Reduction (1) |
Repulsion of electron orbitals allows formation of trans alkene |
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Alkynes: Hydrohalogenation (2) |
Third Order: k [alkyne] [H-X]^2 Regioselectivity: Markovnikov addition excess H-X produces geminal dihalide
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Alkynes: Radical Addition of H-Br (2) |
Regioselectivity: anti-Markovnikov addition Stereoselectivity: mixture of E & Z isomers |
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Alkynes: Acid-Catalyzed Hydration (2) |
Acid-catalyzed tautomerization of enol to ketone Unsymmetrical internal alkyne: yields mixture of possible ketones Terminal alkyne: becomes methyl ketone |
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Alkynes: Hydroboration-oxidation (3) |
Base-catalyzed tautomerization of enol to aldehyde Regioselectivity: anti-Markovnikov addition Terminal alkyne: becomes aldehyde
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Alkynes: Halogenation (2) |
Regioselectivity: anti-Markovnikov Stereoselectivity: E isomer is major product Products include dihalide or tetrahalide when halogen is in excess |
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Alkynes: Ozonolysis (2) |
Internal alkyne: yields identical products with C=O and O-H bonds Terminal alkyne: yields C=O and O-H bonded product and CO2 |
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Alkynes: Alkylation of terminal alkynes (3) |
Strong base deprotonates terminal alkyne SN2 reaction with alkyl halide binds with terminal alkynide ion Acetylene can undergo 2 separate alkylation steps |
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Radical Halogenation (3) |
Chlorine: more reactive Bromine: more selective --> add functional group to alkane New or Existing Chirality Center: Racemic mixture of products due to planar radical intermediate |
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Allylic Radical Bromination (1) |
Produces mixture of products due to resonance stabilized allylic radical |
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Autooxidation (2) |
Produces hydroperoxides Ethers are particularly sensitive to this rxn |
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Radical Addition of H-BR (2) |
Regioselectivity: anti-Markovnikov Stereochemistry: racemic mixture of enantiomers |
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Radical Polymerization of ethylene (1) |
Chain reaction linking ethylene or substituted ethylene molecules together |