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28 Cards in this Set
- Front
- Back
- 3rd side (hint)
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A. Electrophilic addition of H2O to alkene |
Group title |
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Acid Catalyzed Hydration (3) |
H2SO4 in H20 |
- OH on more substituted side of pi bond - Carbocation rearrangement possible - New chirality center = racemic mixture |
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Hydroboration-Oxidation (4) |
1. BH3 : THF 2. H2O2, NaOH |
- OH on less substituted side of pi bond - No carbocation rearrangement - H and OH added syn (concerted) - 1 or 2 new chirality centers = pair of EN |
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Oxymercuration/demercuration (3) |
1. Hg(OAc)2, H2O 2. NaBH4, NaOH |
- OH adds to more substituted side or more stable carbocation - No carbocation rearrangement -H and OH added anti |
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B. Nucleophilic Substitution of Alkyl Halides |
Group Title |
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Nucleophilic Substitution (2) |
Create primary alkyl halide from tertiary: 1. LDA in THF 2. HBr in Peroxide
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SN1: H2O, heat — ter alkyl halide SN2: KOH, polar aprotic solvent — primary alkyl halide
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Anti-Dihydroxylation (2) |
1. MCPBA 2. H3O+ |
- Epoxide formation - Anti-addition of two OH groups to form trans diol |
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Syn-Dihydroxylation (2) |
1. OsO4 2. Na2SO3 or NaHSO3, H2O __________________________________ 1. OsO4 cat. 2. NMO or tert butyl hydroperoxide __________________________________ 1. Cold KMnO4 2. H3O+ |
- Osmate ester formation - Syn addition of two OH groups |
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C. Reduction of Carbonyl Compounds |
Group Title |
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Catalytic Hydrogenation (2) |
H2 Pt, Pd, or Ni |
- All double bonds reduced - Syn addition of H's |
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Sodium Borohydride (3) |
NaBH4 EtOH, MeOH, or H2O |
- Specific for Carbonyl double bond - Reduces aldehydes and ketones - not strong enough to reduce esters |
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Lithium Aluminum Hydride (1) |
1. LiAlH4 2. H2O or dilute H3O+
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- Strong enough to reduce carboxylic acids and esters (creates alkoxide leaving group) |
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D. Organo-metallic Reagents |
Group Title |
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Terminal Acetylides (2) |
1. Na+ (-)acytyl-R 2. H2O or dil. H3O+ or NH4+ (-)Cl
- Reduction of carbonyl with addition of acetyl-R group |
Deprotonate acetylene NaNH2 in NH3(l) |
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Grignard Reagent (3) |
Create Reagent: Mg or Li in dry Et2O or THF
Reduction: 1. R-Mg-X 2. H2O or dil. H3O+ |
- Aldehydes and ketones—intro of R group - Esters and Acyl Chlorides—intro of 2 R groups - Acidic protons (carboxylic acids) are deprotonated into alkoxide ion |
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Alcohol group protection (protect & deprotect) |
Protect: 1. TMSCl, Et3N 2. Mg in dry Et2O or THF
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Deprotect: NaF or CsF or TBAF In dilute H3O+ |
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E. Oxidation of Alcohols |
Group title |
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Chromium Reagents (3) |
Chromic acid: H2CrO4 - H2CrO4 in H2O - CrO3, H2SO4, H2O - Na2Cr2O7, H2SO4, H2O |
Primary alcohol: Aldehyde --> Carboxylic acid Secondary alcohol: Ketone Tertiary alcohol: no H for E2 reaction |
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Pyridinium Chlorochromate (2) |
PCC in CH2Cl2 Create PCC: Pyridine + HCl + CrO3 |
"Dry" primary alcohol: Selects for Aldehyde Secondary alcohol: Ketone (softer reagent) |
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F. Conversion of Alcohols to LG's |
Group title |
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Acid Catalyzed Dehydration (3) |
Conc. H2SO4 |
E1 reaction - Favors more substituted alkene - Carbocation rearrangement possible |
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SN1 reaction (1) |
H-Br |
Tertiary alcohols to tertiary alkyl halides |
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SN2 (2) |
H-Br or HCl in ZnCl2 |
- Primary or Secondary alcohols to primary or secondary alkyl halides - Best method for primary alcohols |
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Tosylate Conversion (2) |
TsCl, Pyridine in NaBr |
- Better method for secondary alcohols — converts to secondary alkyl halide - Inversion of stereochem |
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Switch OH with Br * Inversion (2) |
PBr3 |
- Br added in place of OH - Inversion of stereochemistry |
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Switch OH with Cl * inversion (3) |
SOCl2 in pyridine |
- Cl added in place of OH - Cl kept in solution as salt = Inversion of stereochemistry - SO2 gas released |
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Switch OH with Cl * retention (3) |
SOCl2 |
- Cl added in place of OH - Retention of stereochem - HCl & SO2 gas released |
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Remove OH to form alkene (2) |
POCl3 in pyridine |
- Removes OH group and forms alkene - Better choice than bulky base: no nucleophilic attack from LG |
