Chapter 19, Problem 19.81P

Interpretation Introduction

Interpretation:

Major product of the given has to be predicted. Also reason for why the pathway creates the predominant product is favorable has to beexplained.

Concept Introduction:

Carbonyl compound when treated with LDA (Lithium Diisopropylamide) undergoes deprotonation at the $\text{α}$-carbon to form enolate.  The enolate formed is resonance stabilized as the negative charge will be spread over other atoms too.  The resonance stabilized intermediate undergoes reaction with other molecule of carbonyl (same or different) to form the respective products.  If LDA is used as a base the less substituted $\alpha$ carbon is deprotonated due to steric hindrance.

• Deprotonation of $\alpha$ carbon to form enolate
• Nucleophilic attack of enolate
• S_N2 reaction with alkyl halide

Racemic mixture: A racemic mixture is simply a mixture containing an equal amount of each enantiomer.

Asymmetric center is a sterocenters which arises to hydrocarbons if the carbon is bonded to four different groups.