Horner–Wadsworth–Emmons reaction

Horner–Wadsworth–Emmons reaction
Named after Leopold Horner
William S. Wadsworth
William D. Emmons
Reaction type Coupling reaction
Identifiers
Organic Chemistry Portal wittig-horner-reaction
RSC ontology ID RXNO:0000056

The Horner–Wadsworth–Emmons (HWE) reaction is a chemical reaction used in organic chemistry of stabilized phosphonate carbanions with aldehydes (or ketones) to produce predominantly E-alkenes.

In 1958, Leopold Horner published a modified Wittig reaction using phosphonate-stabilized carbanions. William S. Wadsworth and William D. Emmons further defined the reaction.

In contrast to phosphonium ylides used in the Wittig reaction, phosphonate-stabilized carbanions are more nucleophilic but less basic. Likewise, phosphonate-stabilized carbanions can be alkylated. Unlike phosphonium ylides, the dialkylphosphate salt byproduct is easily removed by aqueous extraction.

Several reviews have been published.