Question

Question:What is the major enolate (or carbanion) formed when each compound is treated with LDA?

Short answer

Answer

The major enolate (or carbanion) formed when each compound is treated with LDA is shown below:-

Step-by-step solution

LDA (Lithium Diisopropyl Amide)

LDA is a non-nucleophilic strong base that abstracts the protons from the least hindered side.Nitrogen is attached with two bulky isopropyl groups, and due to this, it abstracts protons from the less crowded site.

 Step 2: The least hindered site in the given molecules

The least hindered sites in each molecule are shown below:

The product formed in the given reactions

Considering the key steps, the major enolate (or carbanion) formed when each compound is treated with LDA is shown below:-

Reaction a

Reaction b

Reaction c

Reaction d