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Organic Chemistry II 2

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Ways to make alcohols
1.nucleophilic substitution
2.hydride reduction
3.organometallic reagent
Nucleophilic substitution to make alcohols
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
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
1.Na2Cr2O7, H2SO4
or
2.CrO3, H2SO4
Reaction of Metals with Haloalkanes
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
RLi or RMgX + H2O yields RH

RLi or RMgX + H2O yields RD
Reaction of Organometallic Compounds to Aldehydes and Ketones
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
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
-elimination
ROH + H2SO4 yields C=C and water
Formation of Ethers
1.Williamson Synthesis
2.Alcohols and Acid (Mineral Acid Method)
3.Cyclic Ethers
Williamson Synthesis
1.ROH + NaH (DMSO) yield RO- (alkoxide)
2.RO- + R'X yield ROR'
Mineral Acid Method
Alcohol w/ strong acid and water
ROH + H+ yield ROH2 (+ on O)
ROH2 + ROH (remove H20 mol) yield ROR
Cyclice Ethers
-Intramolecular Williamson synthesis
-use NaH and DMF
Reactions of Ethers: Cleavage by Hydrogen Halides
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
-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
RSR' +H2O2 yields R(S=O)R'
R(S=O)R' plus H2O2 yields RSO2R'
Hydrogenation of Alkenes
C=C + H2 (Pd-C or PtO2) yields CH-CH
-syn addition
Alkenes From Haloalkanes
-E2 with sterically hindered base
-Hofmann Rule: less substituted (less stable) alkene
Base: (CH3)3CO-
Solvent: (CH3)3COH
Dehydration of Alcohols
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
C=C + HX yields haloalkane
-markovnikov rule (X on more substituted C)
Electrophilic Hydration of Alkenes
C=C + H2SO4, H2O yields alcohol
-H2SO4 is source of H+
-markovnikov rule
Halogenation of Alkenes
C=C + X2 yields dihaloalkane
-anit addition
-X: Cl2 or Br2 (NOT I2)
Vicinal Haloalcohol Synthesis
C=C + X2,H2O yields haloalcohol
-alcohol on more substituted carbon
-anti addition
Vicinal Haloether Synthesis
C=C + X2,ROH yields haloether
-OR on more substituted carbon
-anti addition
Oxymercuration-Demercuration
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
-Alkene to bromoalkane
-Reagents: BH3 and DMF
-anti-markovnikov (Br on less substituted carbon)
-syn addition
Hydroboration-Oxidation
-Alkene to alcohol
-Reagents: 1)BH3, THF
2)H2O2, NaOH, H2O
-anti-markovnikov alcohol
-syn addition
Carbene Addition to Alkene
-form cyclopropane
-reagent: CH2N2 and hv or heat
-stereospecific (retain configuration)
Oxacyclopropane
-alkene to RCOCR (triangle) and aldehyde
-reagents: RCOOH and CH2Cl2
-stereospecific (syn)
Vicinial Anti Dihydroxylation
-alkene to anti alcohol
-reagents: 1)RCOOH, CH2Cl2
2)H+, H2O
Vicinial Syn Dihydroxylation
-alkene to syn alcohol
-reagents: OsO4, H2S or OsO4, H2O2
Ozonolysis
-alkene to 2 carbonyl compounds
-reagents: 1)O3, MeOH
2)(CH3)2S or Zn and CH3COOH
Radical Hydrobromination
-alkene to anti-markovnikov bromoalkane
-reagents: HBr, ROOR
Radical Sulfide Synthesis
-alkene to antimarkovnikov RSR
-reagents: RSH and ROOR
Alkyne to Ketone
RC(triple bond)CR to RCH2COR
-reagents: Hg2+, H2O
Oxidation of Alkneyboranes
RC=CB yields RCH2COH (aldehyde)
-reagents: 1)H2O2, HO-
2)tautomerism
Radical Allylic Halogenations
RCH2CH=CH2 yields RCHBrCH=CH2 and
RCH=CHCH2Br
-reagents: NBS, CCl4, hv
Allylic Grignard Reagents
CH2=CHCH2Br yields CH2=CHCH2MgBr
-reagents: Mg, Et2O
Allyllithium Reagents
RCH2CH=CH2 yields RCHCH=CH2 Li+
-reagents: CH3CH2CH2CH2Li, TMEDA
Electrophilic Reactions of 1,3 Dienes
-1,2 and 1,4 addition
Halogenation of Benzene
C6H6 yields C6H5X and HX
-reagents: X2, FeX
*X: Cl or Br
Nitration of Benzene
C6H6 yields C6H5NO2 and H2O
-reagents: HNO3, H2SO4
Sulfonation of Benzene
C6H5 yields C6H5SO3H
-reagents SO3, H2SO4
*reversible reaction so remove with H2SO4, H2O, and heat
Benzenesulfonyl Chlorides
C6H5SO3Na yields C6H5SO2Cl and POCl3 and NaC;
-reagent: PCl5
Friedal-Crafts Alkylation
C6H6 yields C6H5R
-reagents: RX and AlCl3
*R+ is subject to rearrangement
Friedal-Crafts Alkylation with alcohols and alkenes as substrates
1.Benzene + RCHOHR' yields C6H5CHR'R
-solvent: BF3
2.Benzene + RCH=CH2 yields C6H5CHRCH3
-solvent:BF
Friedal-Crafts Acylation
Benzene yields C6H5COR
-reagents: 1)RCOCl in AlCl3
2)H2O
Intraconversion of Nitro and Amino Groups on Benzene
1.NO2 + Fe,HCl yields NH2

2.NH2 + CF3CO3H yields NO2
*groups are attached to benzene
Intercoversion of Alkanoyl and Alkyl substituents on Benzene
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
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
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

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