Organic Chemistry II 2
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- Ways to make alcohols
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1.nucleophilic substitution
2.hydride reduction
3.organometallic reagent - Nucleophilic substitution to make alcohols
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1.haloalkane plus CH3COO- (solvent: EtOH) and then NaOH (solvent: H2O)
2.tertiary haloalkane plus H2O2 and propanone - Reduction of Aldehydes and Ketones by Hydrides
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1.NaBH4 and solvent EtOH
2. LiAlH4 (LAD) and solvent Et2OH and then H+, H2O - Primary Alcohol to Aldehyde
- -PCC, CH2Cl2
- Secondary Alcohol to Ketone
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1.Na2Cr2O7, H2SO4
or
2.CrO3, H2SO4 - Reaction of Metals with Haloalkanes
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RX + Li (Et2O) yields RLi
RX + Mg (Et2O) yields RMgX
*R cannot contain acidic groups such as -OH or electrophilic groups such as C=O - Hydrolysis
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RLi or RMgX + H2O yields RH
RLi or RMgX + H2O yields RD - Reaction of Organometallic Compounds to Aldehydes and Ketones
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1. RLi or RMgX plus CH2=O yields primary alcohol (RCH2OH)
2. RLi or RMgX plus Aldehyde yields secondary alcohol
3. RLi or RMgX plus Ketone yields tertiary alcohol
*Aldehyde or Ketone cannot contain other groups that react with organometallic reagents such as OH or other C=O groups - Alkands from Haloalkanes and Lithium Aluminum Hydride
- RX + LiAlH4 (Et2O) yields RH
- Alkoxides from Alcohols
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ROH + strong base yields RO-
*strong base: K+H-; Li+ -N[CH(CH3)2]2; RLi - Bromoalkane from alochol
- PBr3 (SN2 like)
- Iodoalkane from alcohol
- PPh3, I2
- Chloroalkane from alcohol
- SOCl2 and Et3N
- Sulfonate Intermediates
- ROH + R'SO2Cl (pyridine) yields ROSO2R' then Nu with DMF to yields RNu and R'SO3-
- Dehydration of Alcohols with strong nucleophilic acid
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-elimination
ROH + H2SO4 yields C=C and water - Formation of Ethers
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1.Williamson Synthesis
2.Alcohols and Acid (Mineral Acid Method)
3.Cyclic Ethers - Williamson Synthesis
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1.ROH + NaH (DMSO) yield RO- (alkoxide)
2.RO- + R'X yield ROR' - Mineral Acid Method
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Alcohol w/ strong acid and water
ROH + H+ yield ROH2 (+ on O)
ROH2 + ROH (remove H20 mol) yield ROR - Cyclice Ethers
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-Intramolecular Williamson synthesis
-use NaH and DMF - Reactions of Ethers: Cleavage by Hydrogen Halides
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1.ROR + conc. HX yields RX + ROH
2.add conc. HX again yield 2RX
*primary R: Sn2
*secondary R: Sn1 or Sn2
*tertiary R: Sn1 - Epoxides
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-basic nucleophile attack less hindered side (LAD, -SMe, -OMe, R-M)
-acidic conditions attack more hindered side (H+, ROH, halide) - Nucleophilic Opening of Oxacyclopropane by organometallic compounds
- Epoxide (CH2OCH2) + RLi or RMg (THF, then H+,H2O) yields RCH2CH2OH
- Oxidation of Sulfides
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RSR' +H2O2 yields R(S=O)R'
R(S=O)R' plus H2O2 yields RSO2R' - Hydrogenation of Alkenes
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C=C + H2 (Pd-C or PtO2) yields CH-CH
-syn addition - Alkenes From Haloalkanes
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-E2 with sterically hindered base
-Hofmann Rule: less substituted (less stable) alkene
Base: (CH3)3CO-
Solvent: (CH3)3COH - Dehydration of Alcohols
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ROH + H2SO3 (heat) yields C=C
-order of reactivity: primary<secondary<tertiary
-most stable alkene is major product
-primary: E2
-secondary/tertiary: E1
*can have carbocation rearrangement - Electrophilic Addition of HX to alkenes
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C=C + HX yields haloalkane
-markovnikov rule (X on more substituted C) - Electrophilic Hydration of Alkenes
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C=C + H2SO4, H2O yields alcohol
-H2SO4 is source of H+
-markovnikov rule - Halogenation of Alkenes
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C=C + X2 yields dihaloalkane
-anit addition
-X: Cl2 or Br2 (NOT I2) - Vicinal Haloalcohol Synthesis
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C=C + X2,H2O yields haloalcohol
-alcohol on more substituted carbon
-anti addition - Vicinal Haloether Synthesis
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C=C + X2,ROH yields haloether
-OR on more substituted carbon
-anti addition - Oxymercuration-Demercuration
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Alkene to alcohol
Reagents 1)Hg(OC=OCH3)2, H20
2)NaBH4, NaOH, H2O
*if want ether (OR) use ROH instead of H2O
*OH or OR attaches to more substituted carbon - Hydroboration
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-Alkene to bromoalkane
-Reagents: BH3 and DMF
-anti-markovnikov (Br on less substituted carbon)
-syn addition - Hydroboration-Oxidation
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-Alkene to alcohol
-Reagents: 1)BH3, THF
2)H2O2, NaOH, H2O
-anti-markovnikov alcohol
-syn addition - Carbene Addition to Alkene
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-form cyclopropane
-reagent: CH2N2 and hv or heat
-stereospecific (retain configuration) - Oxacyclopropane
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-alkene to RCOCR (triangle) and aldehyde
-reagents: RCOOH and CH2Cl2
-stereospecific (syn) - Vicinial Anti Dihydroxylation
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-alkene to anti alcohol
-reagents: 1)RCOOH, CH2Cl2
2)H+, H2O - Vicinial Syn Dihydroxylation
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-alkene to syn alcohol
-reagents: OsO4, H2S or OsO4, H2O2 - Ozonolysis
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-alkene to 2 carbonyl compounds
-reagents: 1)O3, MeOH
2)(CH3)2S or Zn and CH3COOH - Radical Hydrobromination
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-alkene to anti-markovnikov bromoalkane
-reagents: HBr, ROOR - Radical Sulfide Synthesis
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-alkene to antimarkovnikov RSR
-reagents: RSH and ROOR - Alkyne to Ketone
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RC(triple bond)CR to RCH2COR
-reagents: Hg2+, H2O - Oxidation of Alkneyboranes
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RC=CB yields RCH2COH (aldehyde)
-reagents: 1)H2O2, HO-
2)tautomerism - Radical Allylic Halogenations
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RCH2CH=CH2 yields RCHBrCH=CH2 and
RCH=CHCH2Br
-reagents: NBS, CCl4, hv - Allylic Grignard Reagents
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CH2=CHCH2Br yields CH2=CHCH2MgBr
-reagents: Mg, Et2O - Allyllithium Reagents
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RCH2CH=CH2 yields RCHCH=CH2 Li+
-reagents: CH3CH2CH2CH2Li, TMEDA - Electrophilic Reactions of 1,3 Dienes
- -1,2 and 1,4 addition
- Halogenation of Benzene
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C6H6 yields C6H5X and HX
-reagents: X2, FeX
*X: Cl or Br - Nitration of Benzene
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C6H6 yields C6H5NO2 and H2O
-reagents: HNO3, H2SO4 - Sulfonation of Benzene
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C6H5 yields C6H5SO3H
-reagents SO3, H2SO4
*reversible reaction so remove with H2SO4, H2O, and heat - Benzenesulfonyl Chlorides
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C6H5SO3Na yields C6H5SO2Cl and POCl3 and NaC;
-reagent: PCl5 - Friedal-Crafts Alkylation
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C6H6 yields C6H5R
-reagents: RX and AlCl3
*R+ is subject to rearrangement - Friedal-Crafts Alkylation with alcohols and alkenes as substrates
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1.Benzene + RCHOHR' yields C6H5CHR'R
-solvent: BF3
2.Benzene + RCH=CH2 yields C6H5CHRCH3
-solvent:BF - Friedal-Crafts Acylation
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Benzene yields C6H5COR
-reagents: 1)RCOCl in AlCl3
2)H2O - Intraconversion of Nitro and Amino Groups on Benzene
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1.NO2 + Fe,HCl yields NH2
2.NH2 + CF3CO3H yields NO2
*groups are attached to benzene - Intercoversion of Alkanoyl and Alkyl substituents on Benzene
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1.RC=O + Zn(Hg),HCl,heat yields
RCH2
2.RCH2 + CrO3,H2SO4,H2O yields
RC=O - Blocking of Para position on Benzene by Sulfonation
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1.add SO3H to para position with SO3,H2SO4
2.add E+ to only ortho position
3.remove SO3H with H+,H2O and heat - Interconversion of alcohol and ether substituents on Benzene
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1.OH + NaOH,CH3I yields OCH3
2.OCH3 + conc.HI yields OH - Ortho and Para Directors
- NH2, NHR, NR2, NH(C=O)R, OH, OR, alkyl, phenyl, X
- Meta Directors
- NO2, CF3, NR3, COOH, COOR, RC=O, SO3H, C(triple bond)N