Organic Synthesis

Question 1

Alkene to halogenoalkane
* Reaction name
* Reagent
* Condition
* Mechanism

Answer 1

• electrophilic addition
• condition: room temperature
• reagent: HX or X2

Question 2

Alkene to alkane
* Reaction name
* Condition

Answer 2

• hydrogenation
• condition: nickel catalyst, 150 degrees C

Question 3

Alkene to alcohol
* Reaction name
* Condition
* Mechanism

Answer 3

• acid-catalysed hydration (electrophilic addition)
• conditions:
  * steam
  * solid phosphoric acid
  * 300 degrees C, 60atm

Question 4

Halogenoalkane to alcohol
* Reaction name
* Condition
* Mechanism

Answer 4

• nucleophilic substitution
• condition: warm aqueous NaOH/NaCN

Question 5

Halogenoalkane to amine
* Reaction name
* Condition
* Mechanism

Answer 5

• nucleophilic substitution
• conditions:
  
  • excess NH3
  • heat under reflux in sealed tube
  • high pressure
  • ethanolic solvent

Question 6

Halogenoalkane to nitrile
* Reaction name
* Condition
* Mechanism

Answer 6

• nucleophilic substitution
• condition: warm ethanolic NaCN

Question 7

Thermal cracking
* Conditions
* Products

Answer 7

**Conditions: **
* 600 degrees C
* 70 atm

Products:
* at least one alkene (can be used to make polymers)
* shorter chain hydrocarbons

Question 8

Catalytic cracking
* Conditions
* Products

Answer 8

Conditions:
* zeolite catalyst
* 450 degrees C
* 1-2 atm

Products:
* branched alkanes
* cycloalkanes
* aromatic compounds

Question 9

Halogenoalkane to alkene
* Reaction name
* Condition
* Mechanism

Answer 9

• elimination
• Conditions:
  
  • heat under reflux
  • ethanolic KOH (note: :OH- acts as a base)

Question 10

Alcohols to alkenes
* Reaction name
* Condition
* Mechanism

Answer 10

• acid-catalysed elimination (dehydration)
• Conditions:
  • conc H2SO4
  • steam
  • 300 degrees C
  • 60atm

Question 11

aldehyde/ketone to alcohol
* Reaction name
* Condition
* Why it undergoes that reaction
* Mechanism

Answer 11

nucleophilic addition (reduction)

Conditions:
* NaBH4 in H+ (acidic conditions)
* methanol
* aqueous

Why it undergoes nucleophilic addition:
* aldehydes/ketones are unsaturated
* good leaving group not present

Question 12

Alkane to halogenoalkane
* Reaction name
* Condition
* Steps

Answer 12

free radical substitution

Conditions:
* UV light
* X2

Question 13

primary alcohol to carboxylic acid
* Reaction name
* Condition

Answer 13

(complete) oxidation

Conditions:
* alcohol limited, [O] in excess
* heat under reflux

Question 14

primary alcohol to aldehyde
* Reaction name
* Condition

Answer 14

(partial) oxidation

Conditions:
* alcohol in excess, [O] limited
* aldehyde is distilled off immediately
* distillation

Question 15

secondary alcohols to ketone
* Reaction name
* Condition

Answer 15

oxidation

Condition:
* heat under reflux

Question 16

benzene to nitrobenzene
* Reaction name
* Reagents
* Condition
* Mechanism

Answer 16

electrophilic substitution (nitration)

Reagents & condition:
* conc. HNO3 (nitric acid)
* conc. H2SO4 (sulfuric acid)
* warm

Question 17

benzene to phenyl ketone
* Reaction name
* Reagents
* Condition
* Mechanism

Answer 17

electrophilic substitution (Friedel-Crafts acylation)

Reagents & conditions:
* acyl chloride
* aluminium chloride (AlCl3)
* reflux
* dry ether solvent

Question 18

Alkene to sulfate
* Reaction name
* Condition & reagent
* Mechanism

Answer 18

electrophilic addition
Conditions: room temperature
Reagent: conc. H2SO4

Question 19

Aldehydes/ketones to hydroxynitrile (with HCN)
* Reaction name
* Disadvantage of using HCN
* Mechanism

Answer 19

nucleophilic addition

Disadvantage of using HCN:
* HCN is a weak acid (only partially disassociates); provides insufficient amount of CN- ions
* HCN is a poisonous gas

Question 20

carboxylic acid to primary alcohols

Answer 20

reduction
reagent: LiAlH4 in dry ether

Question 21

Aldehydes/ketones to hydroxynitrile (with KCN)
* reaction name
* condition
* mechanism

Answer 21

nucleophilic addition
Condition: dilute acid