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Reaction Scale Calculator

Pick a stored reaction, fix one reagent's amount, get every other reagent's quantity by stoichiometric equivalents. Solvent volume derived from your substrate concentration. Densities + molar masses come from our molecule database.

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Diels–Alder cycloaddition: cyclopentadiene + maleic anhydride → endo-norbornene-2,3-dicarboxylic anhydride

Diene + Dienophile →[4+2] cyclic adduct

Textbook [4+2] cycloaddition. Electron-rich diene (cyclopentadiene, freshly cracked from its dimer) reacts with electron-poor dienophile (maleic anhydride) in a concerted, suprafacial, endo-selective addition. The endo product crystallises from cold toluene. Frontier-MO analysis predicts the rate (HOMO_diene/LUMO_dienophile gap) and the ortho/endo regio+stereo selectivity — see Houk, JACS 95, 4092 (1973).

Conditions: Run at 20–25 °C in toluene (~1 M substrate) for 1–4 h, or neat above maleic anhydride's mp (~52 °C) for 30 min. No catalyst required — the EDG/EWG-matched pair is fast at room temperature. Cyclopentadiene must be freshly cracked from dicyclopentadiene (170 °C distillation, used within hours). Workup: cool to 0 °C, filter the white crystalline endo product, wash with cold toluene, dry under vacuum.

Expected yield
80–95 %
Expected duration
1–4 h at 20–25 °C in toluene; 30 min neat above 52 °C

Mechanism reference ↗

Scale inputs

Anchor reagent + concentration

Total reactant moles divided by this concentration sets the solvent volume.

Anchor amount

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Computed quantities

Reactants

Reactants for Diels–Alder cycloaddition: cyclopentadiene + maleic anhydride → endo-norbornene-2,3-dicarboxylic anhydride: stoichiometric quantities derived from the anchor amount.
Reagent Equiv Moles · mmol Mass · g Volume · mL
Cyclopentadiene
542-92-7 · C5H6
1.0 10.00 0.661 0.83
Maleic Anhydride
108-31-6 · C4H2O3
1.0 10.00 0.981 0.66

Solvent

Solvent for Diels–Alder cycloaddition: cyclopentadiene + maleic anhydride → endo-norbornene-2,3-dicarboxylic anhydride: stoichiometric quantities derived from the anchor amount.
Reagent Equiv Moles · mmol Mass · g Volume · mL
108-88-3 SDS
108-88-3 · C7H8
186.67 17.200 20.00

Product

Product for Diels–Alder cycloaddition: cyclopentadiene + maleic anhydride → endo-norbornene-2,3-dicarboxylic anhydride: stoichiometric quantities derived from the anchor amount.
Reagent Equiv Moles · mmol Mass · g Volume · mL
826-62-0
826-62-0 · C9H8O3
1.0 10.00 1.642 1.16

Expected isolated yield

What you should actually weigh out of the recrystallisation flask, scaled from the limiting reactant via the canonical-procedure yield window.

Product
826-62-0 826-62-0 · C9H8O3
Theoretical max
1.64 g (10.00 mmol)
Expected isolated · 80–95 % yield
1.31 – 1.56 g

Stoichiometry: moles_X = (moles_anchor / equiv_anchor) × equiv_X. Mass = moles × MW; volume = mass / ρ. Solvent volume = total reactant moles ÷ substrate concentration.

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