Chapters 8, 9, 10: Reactions of Alkenes, Alkynes, Alcohol Synthesis

1) Addition of Hydrogen Halides

HBr

Markonikov

2) Free Radical Addition of HBr

HBr, H2O2

Anti-Markonikov

3) Hydration of Alkenes

H3O+

Markonikov, rearragement

4) Oxymercuraiton-Demurcuraiton

1) Hg(OAc)2 , H2O 2) NaBH4

Markonikov, ANTI

5) Hydroboration

1) BH3-THF 2)H2O2, NaOH

Anti-Markonikov, syn

6) Addition of Halogens

X2

ANTI

7) Formation of Halohydrins

X2 + OH

Markonikov, anti

8) Catalytic hydrogentation

H2, Pt/Pb/Ni

Syn

9) Epoxidation

Peroxyacid

Retains stereochemistry

10) Acid-catalyzed opening of epoxides

H3O+

Anti diols

11) Syn dxhydrogenation of alkenes

a) OsO4, H2O2

b) KMnO4, cold, dilute

12) Oxidative cleavage of alkenes

a) KMnO4, warm, concentrated

• Makes carboxylic acid

b) Ozonolysis (O3, (CH3)2S

• Makes aldehydes

1) Formation of Acetylide Ions

Aklyne + NaNH2

1) A. Synthesis of Alkynes From Acetylide

SN2 attack

1) B. Addition of Acetylide to Carbonyl Groups

Nucleophliic addition

2) Synthesis of Alkenes by Elimination Reactions

A) Dehalohydrogentation

• Two moles of HX

B) KOH at 200ºC to give internal alkynes

C) 1) NaNH2 at 150ºC 2) H2O to give terminal alkynes

3) Addition Reactions of Alkynes 1

A) Catalytic Hydrogenation

B) Partial Hydrogenation to cis alkenes

C) Metal-Ammonia Reduction to trans alkenes

D) Addition of Halogens

E) Addition of Hydrogen Halides

• AntiMARK by adding ROOR

F) Hydration of Alkynes to Ketones and Aldehydes

• Mercuric Ion-Catalyzed Hydration

4) Keto-Enol Tautomerism

5) Hydroboration Oxidation

1) Sia2BH 2) NaOH, H2O2

Anti-Markonikov

6) Oxidation of Alkynes

A) Permanganate oxidation

B) Ozonolysis

3) A. Catalytic Hydrogenation

Addition of two moles of H2 w/ Pt/Pd/Ni

3) B. Partial Hydrogenation

One mole of H2 and Pt/Pd/Ni to give cis alkene

3) C. Metal-Ammonia Reduction

Addition of NaNH2 to give trans alkenes

3) D. Addition of Halogens

1 mole of X2: Forms vinyl dihalides (both cis and trans isomers)

2 moles of X2: Forms tetrahalides

3) E. Addition of Hydrogen Halides

Markonikov

1 mole HX: vinyl halides

2 mole HX: Geminal dihalide

AntiMARK:

Add peroxides (ROOR)

3) F. Hydration of Alkynes to Ketones and Aldehydes

Mercuric Ion-catalyzed hydrogenation

HgSO4/H2SO4

6) A. Permanganate Oxidation

KMnO4

• Neutral, cold —> diketone

  • Terminal —> keto acids

• Basic, warm —> carboxylic acids

6) B. Ozonolysis

1) O3 2) H2O

Carboxylic acids (Same as warm, basic KMnO4)

1) Formation of Alkoxide Ions

ROH + Na or K —> R-O-

2) Formation of Phenoxide Ions

PH-OH + Na or K —> PH-O-

3) Synthesis of Alcohols (Review)

A) SN reaction on alkyl halide (Ch6)

B) From Alkenes

• Acid-Catalyzed Hydrogenation

• Oxymercuration-demercuration

• Hydroboration

• Syn Dihyrdrogenation

  • OsO4 + H2O2

  • KMnO4 (cold, dilute, basic)

• Anti dihydroxylation

  • 1) mCPBA 2) H3O+

• Addition of acetylide to carbonyl groups

4) Organometallic Reagents

A) Grignard

• RX + Mg —> RMgX

B) Organolithium reagents

• 2 Li + RX —> R-Li + LiX

5) Gilman Reagents

2 RLi + CuI —> (R)2CuLi + LiX

6) Side reactions of organometallic reagents

React with acidic compounds (OH, NH, SH, C≡C-H)

React with electrophilic multiple bonds (C=O, C=N, C≡N, S=O, N=O)

7) Reduction of Carbonyl Groups

A) Sodium Borohydride (NaBH4)

• Reacts with aldehydes, ketones

• NOT esters or carboxylic acids

B) Lithium Aluminum hydride (LiAlH4)

• Reacts with aldehydes, ketones, esters, and carboxylic acids

  • Much stronger

C) Rainey Ni

• Adds hydrogen to ALL double bonds

8) Thiols (mercaptans)

Synthesized though SN2 reaction with halides

Thiol oxidation:

• Br2 to form disulfide

• Zn, HCl to separate disulfide back into two thiol molecules

Esterification

1) Reacitons with carboxylic acids with H2SO4

2) Reactions with Acyl chloride (H of OH and Cl of acid chloride leave and bond is formed)

3) Wiliamson Ether Synthesis

• Alkoxide + primary halide or tosylate

• SN2