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Horner–Wadsworth–Emmons reaction template
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Triethyl phosphonoacetate is deprotonated, adds to benzaldehyde and the oxaphosphetane collapses to ethyl cinnamate and diethyl phosphate.
Mechanism step by step
A phosphonate carbanion makes an E-α,β-unsaturated ester
- Carbanion – The CH₂ between P=O and C=O is acidic
- Addition – The carbanion attacks the aldehyde
- Oxaphosphetane – The alkoxide attacks phosphorus
- Collapse – C=C forms; diethyl phosphate leaves
Key points
- Phosphonate carbanions are more nucleophilic and less basic than Wittig ylides.
- Strongly E-selective: the anti intermediate eliminates fastest.
- The phosphate by-product is water-soluble, so work-up is easy.
- Still–Gennari phosphonates (CF₃CH₂O groups) reverse the selectivity to Z.
Drawn with 185 atoms, 13 arrows, 6 shapes – every one editable in MolDraw.
Sources
- Horner, Hoffmann & Wippel, Chem. Ber. 1958, 91, 61 Original paper
- Wadsworth & Emmons, J. Am. Chem. Soc. 1961, 83, 1733 Original paper
- Kürti & Czakó, Strategic Applications of Named Reactions in Organic Synthesis, Elsevier 2005 Textbook
- Clayden, Greeves & Warren, Organic Chemistry, 2nd ed., OUP 2012 Textbook
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Frequently asked questions
Is the Horner–Wadsworth–Emmons reaction template free?
You can preview the Horner–Wadsworth–Emmons reaction template here and open and edit it in MolDraw for free. Downloading or exporting it is part of MolDraw Pro, together with the other premium templates.
Can I edit the Horner–Wadsworth–Emmons reaction template?
Yes. It opens as an ordinary MolDraw drawing, so every structure, arrow, label and colour can be changed, and you can add your own content around it.
Is the chemistry checked?
Every structure is checked with RDKit and every curly arrow passes MolDraw’s electron-flow audit. The sources used are listed on this page.
Which name reactions are included?
Over seventy, covering the reactions most often asked in school-leaving exams (A-level, IB, CBSE, JEE and NEET) and first-year university courses, including condensations, rearrangements, oxidations, reductions and aromatic substitutions.