--- title: "Prins reaction Template – Chemistry Diagram | MolDraw" url: https://www.moldraw.com/templates/prins-reaction/ description: "Prins reaction template: Acid protonates formaldehyde; 2-methylpropene attacks it to give the tertiary carbocation, which water traps…" lang: en publisher: Scidart Academy generated: 2026-11-13 --- [MolDraw](https://www.moldraw.com/) › [Templates](https://www.moldraw.com/templates/) › [Name reactions](https://www.moldraw.com/templates/name-reactions/) › Prins reaction [Name reactions](https://www.moldraw.com/templates/name-reactions/)Premium # Prins reaction template ![Prins reaction template: Acid protonates formaldehyde; 2-methylpropene attacks it to give the tertiary carbocation, which water traps: 3-methylbutane-1,3-diol after loss of a proton.](https://www.moldraw.com/templates/prins-reaction.webp) [Edit in MolDraw](https://www.moldraw.com/)Download with Pro Premium template. Preview and edit it free in MolDraw; downloading and exporting it is part of [MolDraw Pro](https://www.moldraw.com/pricing). Acid protonates formaldehyde; 2-methylpropene attacks it to give the tertiary carbocation, which water traps: 3-methylbutane-1,3-diol after loss of a proton. ## Mechanism step by step An alkene adds to protonated formaldehyde; water traps the cation to give a 1,3-diol 1. **Protonation** – Acid protonates formaldehyde: an oxocarbenium ion 2. **C–C bond formation** – The alkene attacks through its CH₂ end, giving the more stable tertiary cation (Markovnikov) 3. **Water traps the cation** – Water adds to the tertiary carbocation 4. **Deprotonation** – Water takes a proton: the 1,3-diol and the acid catalyst back ## Key points - Electrophilic addition of an alkene to a protonated aldehyde (usually formaldehyde): a new C–C bond and a 1,3-relationship of the two oxygens. - The product depends on the conditions: with water a 1,3-diol; without a nucleophile loss of H⁺ gives an allylic or homoallylic alcohol (2-methylpropene → 3-methylbut-3-en-1-ol); with excess formaldehyde a 1,3-dioxane. - Markovnikov: the alkene bonds through the carbon that leaves the more stable carbocation. - Lewis-acid and intramolecular Prins cyclisations make tetrahydropyrans (the oxa-Prins route in natural-product synthesis). Drawn with 63 atoms, 12 arrows, 6 shapes – every one editable in MolDraw. ## Sources - [Kürti & Czakó, Strategic Applications of Named Reactions in Organic Synthesis, Elsevier 2005](https://openlibrary.org/isbn/9780124297852) Textbook - [Smith, March's Advanced Organic Chemistry, 8th ed., Wiley 2020, ch. 16](https://openlibrary.org/isbn/9781119371809) Textbook ## How to use this template 1. Press **Edit in MolDraw**. The template opens on the canvas of the free MolDraw editor. 2. Change anything: move structures, edit atoms and labels, recolour highlights or delete what you do not need. 3. Add your own structures, arrows and text next to it, or combine several templates on one page. 4. Export the drawing as PNG, SVG or PDF for slides, worksheets, theses and papers. ## Frequently asked questions ### Is the Prins reaction template free? You can preview the Prins 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 Prins 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? 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