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Wittig reaction template
![Wittig reaction template: Phosphonium salt, ylide, [2+2] cycloaddition to the oxaphosphetane and its collapse to methylenecyclohexane and Ph₃P=O.](/templates/wittig-reaction.webp)
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Phosphonium salt, ylide, [2+2] cycloaddition to the oxaphosphetane and its collapse to methylenecyclohexane and Ph₃P=O.
Mechanism step by step
A phosphorus ylide turns C=O into C=C; Ph₃P=O is the driving force
- Phosphonium salt – Ph₃P displaces bromide (SN2)
- Ylide – BuLi removes a C–H next to P⁺
- Oxaphosphetane – C–C and O–P bonds form together ([2+2])
- Collapse – Retro-[2+2]: C=C and P=O form
Key points
- The very strong P=O bond (≈ 575 kJ mol⁻¹) drives the reaction.
- The C=C appears exactly where the C=O was: no isomer mixtures.
- Unstabilised ylides (R = alkyl) give mainly Z-alkenes; stabilised ylides (R = CO₂Et) give E.
- Horner–Wadsworth–Emmons uses phosphonate anions and gives E-alkenes.
Drawn with 103 atoms, 13 arrows, 10 shapes – every one editable in MolDraw.
Sources
How to use this template
- Press Edit in MolDraw. The template opens on the canvas of the free MolDraw editor.
- Change anything: move structures, edit atoms and labels, recolour highlights or delete what you do not need.
- Add your own structures, arrows and text next to it, or combine several templates on one page.
- Export the drawing as PNG, SVG or PDF for slides, worksheets, theses and papers.
Frequently asked questions
Is the Wittig reaction template free?
You can preview the Wittig 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 Wittig 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.