Chapter 18, Problem 18.91P

Interpretation Introduction

Interpretation:

The complete and detailed mechanism for the given example of Wittig-Horner’s reaction is to be drawn.

Concept introduction:

Wittig-Horner's reaction is a similar mechanism like Wittig's reaction. The reaction of a carbonyl compound with stabilized phosphorus ylides or phosphonate carbanions leads to olefins with E-selectivity. Butyl lithium is a strong enough base to deprotonate the carbon and make a carbon nucleophilic that can attack the carbonyl compound in nucleophilic addition. Followed by the nucleophilic addition, the P-O bond produces an intermediate of an epoxide. Reactive ylide gives the final product after the rapid ring opening of the epoxide.