Carbanion

Question 1

What is carbanion?

Answer 1

It is an sp3 hybridised carbon with a negative charge and is pyramidal.

Question 2

What are the methods of generation of carbanion?

Answer 2

1. From organometallic compounds.
   C-EN + Metal —> C-Metal-EN
2. By Abstraction of Alpha Hydrogen
   Any anion has two action either act as a nucleophile (first priority) or base .
3. By heating carboxylate anion
4. By metal

Question 3

What is the nature of alpha hydrogens of carbonyl group?

Answer 3

Acidic

Question 4

What is special about the organometallic bond?

Answer 4

It is neither 100% covalent nor 100% ionic.

Question 5

Reactions of Carbanion

Answer 5

1. Acts as base: lone pair of electrons is donated to H+ (Acidic H)
2. Acts as Nucleophile: l.p. to Carbon

Question 6

When is the Hydrogen acidic?

Answer 6

When it is attached to a highly EN atom or stability is gained after its removal.

Question 7

Reactions with Grignards Reagent

Answer 7

1. With Methanal and H2O/H+: Primary Alcohol
2. With Aldehydes [except methanal] and H2O/H+: Secondary Alcohol
3. With Ketone and H2O/H+: Tertiary Alcohol