--- title: "Electrocyclic ring closure Template – Chemistry Diagram | MolDraw" url: https://www.moldraw.com/templates/pericyclic-electrocyclic/ description: "Electrocyclic ring closure template: (2E,4Z,6E)-Octa-2,4,6-triene closes disrotatory to cis-5,6-dimethylcyclohexa-1,3-diene; (2E,4E)-hexa-2,4-diene closes…" lang: en publisher: Scidart Academy generated: 2026-10-28 --- [MolDraw](https://www.moldraw.com/) › [Templates](https://www.moldraw.com/templates/) › [Pericyclic reactions](https://www.moldraw.com/templates/pericyclic-reactions/) › Electrocyclic ring closure [Pericyclic reactions](https://www.moldraw.com/templates/pericyclic-reactions/)Premium # Electrocyclic ring closure template ![Electrocyclic ring closure template: (2E,4Z,6E)-Octa-2,4,6-triene closes disrotatory to cis-5,6-dimethylcyclohexa-1,3-diene; (2E,4E)-hexa-2,4-diene closes conrotatory to trans-3,4-dimethylcyclobutene.](https://www.moldraw.com/templates/pericyclic-electrocyclic.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). (2E,4Z,6E)-Octa-2,4,6-triene closes disrotatory to cis-5,6-dimethylcyclohexa-1,3-diene; (2E,4E)-hexa-2,4-diene closes conrotatory to trans-3,4-dimethylcyclobutene. ## Mechanism step by step Thermal 6π closures are disrotatory, thermal 4π closures conrotatory (Woodward–Hoffmann) 1. **6π, thermal** – Disrotatory: the HOMO ψ3 has the same phase at both termini, so both methyls turn the same way out: cis 2. **4π, thermal** – Conrotatory: the HOMO ψ2 has opposite phases at the termini, so the methyls end up trans ## Key points - Woodward–Hoffmann table: 4n π electrons close conrotatory by heat, disrotatory by light; 4n + 2 π electrons close disrotatory by heat, conrotatory by light. - FMO: look at the HOMO termini; light promotes an electron, so the new HOMO (one level up) has the opposite symmetry. - Stereospecific: (E,Z,E)-octatriene gives only cis-5,6-dimethylcyclohexadiene by heat; (E,E)-hexadiene gives trans-3,4-dimethylcyclobutene. - The 4π cyclobutene–butadiene equilibrium lies on the open side (ring strain): the conrotatory ring opening is the one usually seen. Drawn with 44 atoms, 8 arrows, 4 shapes – every one editable in MolDraw. ## Sources - [Woodward & Hoffmann, Angew. Chem. Int. Ed. Engl. 1969, 8, 781](https://doi.org/10.1002/anie.196907811) Review - [Fleming, Molecular Orbitals and Organic Chemical Reactions, Wiley 2010](https://openlibrary.org/isbn/9780470746585) Textbook - [Clayden, Greeves & Warren, Organic Chemistry, 2nd ed., OUP 2012, ch. 35](https://openlibrary.org/isbn/9780199270293) 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 Electrocyclic ring closure template free? You can preview the Electrocyclic ring closure 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 Electrocyclic ring closure 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. ### Do the pericyclic templates show orbital symmetry? They show the curly arrows, the stereochemical outcome and the Woodward–Hoffmann rule that predicts it (conrotatory or disrotatory, endo or exo). ## More pericyclic reactions templates [**Diels–Alder reaction: the endo rule**Free · Pericyclic reactions](https://www.moldraw.com/templates/pericyclic-diels-alder-endo/)[**Diels–Alder regiochemistry**Free · Pericyclic reactions](https://www.moldraw.com/templates/pericyclic-diels-alder-regio/)[**Cope and oxy-Cope rearrangements**Free · Pericyclic reactions](https://www.moldraw.com/templates/pericyclic-cope-oxy-cope/)[**Claisen rearrangement**Premium · Pericyclic reactions](https://www.moldraw.com/templates/pericyclic-claisen/)[**1,3-Dipolar cycloaddition**Premium · Pericyclic reactions](https://www.moldraw.com/templates/pericyclic-dipolar-cycloaddition/) ## Related pages [**Curved Arrow Mechanism Worksheet**Free printable worksheet](https://www.moldraw.com/educational-materials/curved-arrow-mechanism-worksheet/)[**All Pericyclic reactions templates**6 templates](https://www.moldraw.com/templates/pericyclic-reactions/)[**All chemistry templates**370 templates in 29 categories](https://www.moldraw.com/templates/) MolDraw Pro Download all 370 templates - Export the 291 premium templates as PNG, SVG or PDF - AI chemistry assistant - Structure scanning from images - Cloud save and teaching slides [See Pro plans](https://www.moldraw.com/pricing) Free templates stay free. 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