Exercise 94 - Electrophilic/Nucleophilic Addn To CO, etc.

C

N

CH

3

C

O

H

3

C

H

Provide a mechanism for each of the following addition reactions. Indicate whether they
are nucleophilic or electrophilic. How can you tell the difference?

C

HO

OCH

3

H

3

C

H

H

+

, CH

3

OH

The formation of a hemiacetal from an
aldehyde, the first part of acetal
formation.

1) PhLi
2) H

3

O

+

C

N

H

CH

3

Ph

The formation of an imine from a nitrile, the
first part of the transformation of nitriles to
ketones.

C

N

H

CH

3

Ph

H

3

O

+

C

H

2

N

CH

3

Ph

OH

Formation of a hemiaminal from an
imine, the first half of imine hydrolysis
to a ketone

C

N

CH

3

H

3

O

+

C

N

H

CH

3

HO

The first part of nitrile hydrolysis.

CH

OH

CH

3

Ph

C

O

H

3

C

H

1) PhLi
2) H

3

O

+

C

O

H

3

C

H

C

HO

NH

2

H

3

C

H

NH

3

pH = 6

The first step in the formation of an
imine via addition - elimination.