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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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Mitsunobu reaction: benzyl alcohol + phthalimide → N-benzyl phthalimide

R–OH + Nu–H + PPh3 + DIAD → R–Nu + PPh3=O + reduced DIAD

PPh3/DIAD-mediated dehydrative coupling of an alcohol with an acidic pronucleophile (pKa ≲ 13). Phthalimide as the nucleophile gives an N-alkyl phthalimide that hydrolyses to the free primary amine — the classic Gabriel-like sequence. SN2 mechanism with clean inversion of configuration at the alcohol carbon. PPh3 is oxidised to PPh3=O; DIAD is reduced to the corresponding hydrazine. Both byproducts complicate purification — chromatography is usually required.

Conditions: PPh3 (1.1 equiv) and DIAD (1.1 equiv) in dry THF (1.0 M based on alcohol). Add DIAD slowly to a stirred mixture at 0 °C, then warm to room temperature and stir for 4–12 h (overnight is safest). Argon atmosphere; DIAD reduces explosively at >100 °C. Workup: concentrate, redissolve in EtOAc, wash with sat. NaHCO3 + brine, dry MgSO4, evaporate. Column chromatography (hexane/EtOAc, gradient) removes PPh3=O and the spent hydrazine.

Expected yield
70–90 %
Expected duration
4–12 h (commonly overnight) at 0 °C → room temperature

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 Mitsunobu reaction: benzyl alcohol + phthalimide → N-benzyl phthalimide: stoichiometric quantities derived from the anchor amount.
Reagent Equiv Moles · mmol Mass · g Volume · mL
Benzyl Alcohol
100-51-6 · C7H8O
1.0 10.00 1.081 1.04
Phthalimide
85-41-6 · C8H5NO2

density unavailable — volume not calculable.

1.1 11.00 1.618

Catalyst

Catalyst for Mitsunobu reaction: benzyl alcohol + phthalimide → N-benzyl phthalimide: stoichiometric quantities derived from the anchor amount.
Reagent Equiv Moles · mmol Mass · g Volume · mL
603-35-0
603-35-0 · C18H15P
1.1 11.00 2.885 2.67
2446-83-5
2446-83-5 · C8H14N2O4

density unavailable — volume not calculable.

1.1 11.00 2.224

Solvent

Solvent for Mitsunobu reaction: benzyl alcohol + phthalimide → N-benzyl phthalimide: stoichiometric quantities derived from the anchor amount.
Reagent Equiv Moles · mmol Mass · g Volume · mL
109-99-9
109-99-9 · C4H8O
530.72 38.270 43.00

Product

Product for Mitsunobu reaction: benzyl alcohol + phthalimide → N-benzyl phthalimide: stoichiometric quantities derived from the anchor amount.
Reagent Equiv Moles · mmol Mass · g Volume · mL
2142-01-0
2142-01-0 · C15H11NO2
1.0 10.00 2.373

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
2142-01-0 2142-01-0 · C15H11NO2
Theoretical max
2.37 g (10.00 mmol)
Expected isolated · 70–90 % yield
1.66 – 2.14 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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