MolDraw › Templates › Pericyclic reactions › Diels–Alder reaction: the endo rule
Diels–Alder reaction: the endo rule template
Free template. Download it, or open it in MolDraw to change it first.
Cyclopentadiene adds to maleic anhydride through the endo transition state: three curly arrows round a six-membered ring give cis-norbornene-endo-2,3-dicarboxylic anhydride.
Mechanism step by step
Cyclopentadiene and maleic anhydride give the endo adduct, a concerted [4+2] cycloaddition
- [4+2] Cycloaddition – Six electrons move round the ring in one step: diene HOMO, dienophile LUMO
Key points
- FMO: the diene HOMO (ψ2) overlaps the dienophile LUMO (π*); C=O groups lower the LUMO and speed the reaction.
- Suprafacial on both components [π4s + π2s]: thermally allowed, six electrons (4n + 2).
- Endo rule: the C=O groups sit under the diene in the transition state; secondary orbital overlap makes the endo adduct the kinetic product.
- Stereospecific: cis groups on the dienophile stay cis in the product.
Drawn with 48 atoms, 5 arrows, 3 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.
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Frequently asked questions
Is the Diels–Alder reaction: the endo rule template free?
Yes. The Diels–Alder reaction: the endo rule template is one of the free MolDraw templates: open it in the editor or download it from this page as SVG or PNG and use it in your slides, worksheets and notes.
Can I edit the Diels–Alder reaction: the endo rule 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).