Aliphatic Organic Synthesis

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Illustrated reference for common synthesis reactions that a first year organic chemistry student should know. Alkenes, Alkyl Halides, Alcohols, and others.

Text of Aliphatic Organic Synthesis

Aliphatic Organic Synthesis Routes

1

Reactions of Alkenes, Alkanes and Epoxyethane

R H Major C Br

H C H Haloalkane H H

R C H

H C Br H Minor R H C Br H C Br H

Electrophilic addition

HBr

Br2r.t.p. Electrophilic addition H C H H C H Alkane H

C

Cn

H High temp and pressure Add. Pol R

C

H Hydrogen, Ni cat, 180 C C R Hydrogentation H

OH2 300 C/ 60atm Electrophilic H3PO4Cat addition R H C O H

O2 [O] Ag cat 250 C H C H

H R C

C H O Expoxethane ROH H H C H

Dil H2SO4 cat @ 60 C 200 c 1400 KPa

H H Alcohol R C

H R C OH

H C OH H Diol

OR OH Ether

2

Reactions of Alkenes.1. Alkene C2H4 +Br2 Reagent: Conditions: Type: Mechanism:H C H Br Br C

Dihaloalkane BrCH2CH2Br Br2 r.t.p. Electrophilic addition Required.H H H H C Br Br H C+

AS P192

H H H C Br

H C Br H

2.

Alkene

haloalkane 3

AS P192

C2H3R +HBr Reagent: Conditions: Type: Mechanism:H C H H Br C

RCH2CH2Br HBr r.t.p. Electrophilic addition Required.H H H H C H Br H C+

H H H C H

H C Br H

H3C H

C

C

H H H

CH3 H C H Br primary Carbocation C+

CH3 H H H C H C Br minor product H

H Br

H3C H

C

C

H H H3C H C+

H C H H H

CH3 H C Br C H Major product H

H Br

Br Secondary Carbocation

3.

Alkene

Alcohol

AS P193

4

C2H3R +H2O Reagent: Conditions: Type: Mechanism:H C H C H H

RCH2CH2OH H2O/H3PO4 cat. Or H2SO4 cat. 3000C/ 60 atm Electrophilic addition Required.H H O O O O H H C H H C H H O O S O O

S

H H C H

H C H O HO S O O H + OH2 H C H H C H O H

+

H2SO4

4.

Alkene C2H3R +O2 Reagent: Conditions: Type: Mechanism: O2 Ag cat. 250oC Oxidation Not required.

Epoxyethane RCHOCH2

AS P196

H C R C

H H R

H C O

H C H

5.

Alkene

Alkane 5

AS P195

C2H3R +H2 Reagent: Conditions: Type: Mechanism: H2 / Ni cat 180oC

RCH2CH3

Electrophilic addition Not Required.

Reactions of Epoxyethane6. Epoxyethane Diol AS P197

6

RCHOCH2 +H2O Reagent: Conditions: Type: Mechanism:H H C O H C H

RCHOHCH2OH

Dil H2SO4 cat. @ 60oC 200oC, 1400 kPa

Not required.H H C OH H

+

OH2

H

C OH

7.

Epoxyethane RCHOCH2 Reagent: Conditions: Type: Mechanism:H H C O H C H

Ether RCHORCH2OH Dil H2SO4 cat. @ 60oC 200oC, 1400 kPa

AS P197

Not required.H H C OH H

+

ROH

H

C OR

Reactions of Alkanes8. Alkane RC2H5 +Cl2 Haloalkane RCH2CH2Br 7 AS P192

Reagent: Conditions: Type: Mechanism:

Cl2 U.V.light Free radical substitution Required.

Cl

Cl

Cl

+

Cl

Cl

+

H

CH3

HCl

+ +

CH3

CH3

+

Cl

Cl

CH3Cl

Cl

Cl Cl CH3

+ + +

Cl CH3 CH3

Cl2 CH3Cl C2H6

Reaction of Haloalkanes and Nitriles

8

H R C

H C O H

H H Alcohol

NaoH (aq) Reflux

Nucleo Sub

H H C R alkene C R H OH- Alocoholic soln reflux H Elimination C

H C

H H H Conc NH3 heat in a sealed tube H Br R C C Nucleo Haloalkane H Sub H amine Nucleo KCN, alocoholic Sub Solution, reflux H H C CN+

NH2

H2 / LiAlH4

R

C H

H

Reduction H R C H H C H NH2

Hydrolysis

H /H2O, reflux H R C H H C H C OH O

amine

Carboxylic acid

Reaction of Haloalkanes9. Haloalkane RCH2CH2Br +NaOH Alcohol RCH2CH2OH AS P209

9

Reagent: Conditions: Type: Mechanism: H H C H H C H

NaOH (aq) Heat under reflux Nucleophilic substitution Required.

Br H OH

H C H

H C H OH

10.

Haloalkane RCH2CH2Br +NH3 Reagent: Conditions: Type: Mechanism:H H C H H C H NH3 Br H H C H

Amine RCH2CH2NH2

A2 P88

NH3 Heat Nucleophilic substitution Required.

H C H

H N H NH3+

H H H C H

H C H N

H H

+

NH4Br

11.

Haloalkane RCH2CH2Br + KOH Reagent: Conditions: Type: KOH in ethanol Heat under reflux Elimination

Alkene RCH2CH2

AS P212

10

Mechanism:

Required.

H R C H

H C H OH Br H C H C H H

12.

Haloalkane RCH2CH2Br +KCN Reagent: Conditions: Type: Mechanism: KCN in ethanol Heat under reflux

Nitrile RCH2CH2CN

A2 P90

Nucleophilic substitution Required

H R C H

H C H CN Br R

H C H

H C H CN

Reaction of Nitriles13. Nitrile RCH2CH2CN Amine RCH2CH2CH2NH2 A2 P90

11

Reagent: Conditions: Type: Mechanism:

LiAlH4, dry ether r.t.p. Reduction Not required.

H2, Ni cat

H R C H

H C H CN

H

H C H

H C H N

+

H H

4[H]

R

C H

14.

Nitrile RCH2CH2CN Reagent: Conditions: Type: Mechanism:H R C H H C H CN

Carboxylic acid RCH2CH2CH2COOH H+/H2O H.U.R Hydrolysis Not requiredH H C H H C H COOH

+

H Cl

+ H2 O

R

C H

12

Reaction of AlcoholsH R C H H C H C OH O

Carboxylic acid

H+/

oxidation Cr2O 72(aq), reflux

reduction

H R C H

H C C

O H H R oxidation C H H C H ester Hydrolysis O C R

H Aldehyde

H+/

Cr2O 72(aq),

-

reflux

NaBH4

Esterification R'COOH/H+, reflux

H R C

H C O H H+ or OH- (aq)

H H 1o Alcohol

Al2O3300 C or Conc H2SO4 180 C

Dehydration H C C R alkene Dehydration Al2O3300 C or Conc H2SO4 180 C CH3

H H

H R C H

H C H Ketone

H+/ Cr O 2(aq), reflux H 2 7 oxidation C C R reduction CH3 NaBH4 H O

H C

OH 2o Alcohol

Reaction of Primary Alcohols13

15.

1o Alcohol RCH2CH2OH Reagent: Conditions: Type: Mechanism: H H C H 16. 1o Alcohol RCH2CH2OH Reagent: Conditions: Type: Mechanism: H H C H H C H O H K2Cr2O7/H2SO4 HUR Oxidation Not required. H C H O H K2Cr2O7/H2SO4 Heat under distillation Oxidation Not required.

Aldehyde RCH2CH2CHO

AS P223 A2 P62

[O] H

H C H

H C H CHO

Carboxylic acid RCH2CH2COOH

AS P223 A2 P62

[O] H

H C H

H C H COOH

17.

1o Alcohol RCH2CH2OH Reagent: Al2O3 / H2SO4

Alkene RCHCH2

AS P227

14

Conditions: Type: Mechanism:H H C H H C H

180oC Dehydration Required.

H O H H+

H C H + O H H H

H C H

H C+ H

H

C H

H C H C

H H

18.

1o Alcohol RCH2CH2OH Reagent: Conditions: Type: Mechanism:H H C H H C H O H

Ester RCH2CH2OCOR RCOOH / HCl HUR Esterification Not required.H H C H COOH H

A2 P67

H C H

H C H O C

+H

O R

C H

19.

1o Alcohol RCH2CH2OH Reagent: Conditions: NaX Conc. H2SO4 HUR 15

Haloalkane RCH2CH2X

Type: Mechanism: H H C H H C H

Nucleophilic substitution Not required. H O H H C H X H C H X

Reaction of Secondary Alcohols20. 2o Alcohol Ketone AS P223

16

RCHOHCH3 + [O] Reagent: Conditions: Type: Mechanism: H R C H C H K2Cr2O7/H2SO4 Heat under Reflux Oxidation Not required

RCOCH3

[O] R

H C O

H C H H

OH H

Reactions of Aldehydes and ketones

17

Carboxylic acid H H R C H reduction C H C

O OH

H+/ Cr O 2(aq), reflux 2 7

XH Ketone R C H H C H C R' H+/ Cr O 2(aq), reflux 2 7 O R reduction

oxidation H C H H C H H+/ C

Aldehyde H C OH CN

OHCN R H

H C H

H C H

Cr2O72(aq), reflux

Hydroxynitrile

LiAlH4ether oxidation H R C H H C OH CH3

LiAlH4ether oxidation H R C H H C H O H

2o Alcohol

1o Alcohol

Reactions of Aldehydes21. Aldehyde RCH2CHO Reagent: Conditions: Type: Mechanism: K2Cr2O7/H2SO4 Heat under Reflux Oxidation Not required 18 Carboxylic acid RCH2COOH A2 P63

H H C H 22. Aldehyde RCH2CHO Reagent: Conditions: Type:

H C H 1o Alcohol RCH2CH2OH NaBH4, ether r.t.p. Reduction Not requiredH CHO H C H

CHO

[O] H

H C H

H C H COOH

A2 P63

Mechanism:H H C H H C H

H C H

H C H OH

23.

Aldehyde RCH2CHO Reagent: Conditions: Type: Mechanism:R C H

Hydroxynitrile RCHOHCN HCN r.t.p. Nucleophilic addition RequiredH O R C CN O H+

A2 P64

H R C CN OH

CN

19

Reactions of Ketones24. Ketone RCOCH3 Reagent: Conditions: Type: Mechanism:H R C O H H O H C H H R

2o Alcohol RCHOHCH3 LiAlH4, ether r.t.p. Reduction Not requiredH C O H C H H

A2 P66

H R C

H C H

OH H

20

Reactions of Carboxylic acids

21

NAE H R C H H C H Ester O cat R'OH/concH2SO4 reflux H H O O Esterification NAE C R C C C H+(aq)/ H2O OH R H H NAE Carboxylic acid reduction H2O NAE CH3 CH3 C

O

O C O Acid Anhydride

H+/ Cr O 2(aq), reflux 2 7

LiAlH4ether H R C H

oxidation H C H O H

1o Alcohol

Reactions of Carboxylic acids

25.

Carboxylic acid 22

1oAlcohol

A2 P63

RCH2COOH Reagent: Conditions: Type: Mechanism: H R C H H C H COOH LiAlH4, ether r.t.p. Reduction Not required

RCH2CHOH

H R C H