Synthesis

Question 1

What 4 ways can be used to extend a carbon chain

Answer 1

1. Reacting a halogenoalkane with a cyanide ion forms a nitrile with one more carbon atom than the halogenoalkane
2. The addition of hydrogen cyanide to a carbonyl compound
3. The alkylation of benzene, introduced an alkyl group into a benzene ring.
4. The use of a Grignard reagent

Question 2

How are Grignard made?

Answer 2

Heating under reflux the chosen halogenoalkane or haloarene with magnesium in a solvent of dry ether

Question 3

What do Grignard reagents involve the use of
Which element

Answer 3

Organometallic compounds containing magnesium

Question 4

How is the magnesium’s bonded to and which type of bond

Answer 4

Covalently to both the alkyl group and halogen

Question 5

General equation for the formation of a Grignard reagent

Answer 5

R-Br + Mg —> R-Mg-Br

Question 6

Grignard reaction with CO2
Give the equation, name of product and how many carbons added

Answer 6

RMgBr —> RCOOH
Carboxylic acid
Increase by 1 carbon atom

Question 7

Grignard reaction with methanal
Give the equation, name of product and how many carbons added

Answer 7

RMgBr —> RCH2OH
Primary alcohol
Increased by 1 carbon atom

Question 8

Grignard reaction with aldehyde
Give the equation, name of product and how many carbons added

Answer 8

RMgBr —> R1R2CHOH
Secondary alcohol
Increased by as many carbon atoms in R1 and R2

Question 9

Grignard reaction with ketone
Give the equation, name of product and how many carbons added

Answer 9

RMgBr —> R1R2R3COH
Tertiary alcohol
Increased by as many carbon atoms in R1, R2 and R3

Question 10

What is done after the Grignard reaction

Answer 10

A dilute acid is added to obtain the desired organic product