Q61. - Organic Chemistry

Question

Question: A key step in the synthesis of β-vetivone, a major constituent of vetiver, a perennial grass found in tropical and subtropical regions of the world, involved the reaction of compound A and dihalide B with two equivalents of LDA to form C. Draw a stepwise mechanism for this reaction. β-Vetivone contains a spiro ring system—that is, two rings that share a single carbon atom.

Step-by-Step Solution

Answer

Answer

Step 1: Lithium diisopropylamide

Lithium diisopropylamide (LDA) is a strong base that does not act as a nucleophile and hence can be used to abstract protons from a compound.

Step 2: Mechanism of the given reaction

The given reaction involves the following steps:

• Abstraction of the acidic proton using LDA.
• The reaction of carbanion with alkene and the formation of a new C-C (carbon-carbon) bond.

                                    Mechanism of the reaction