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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 ↗

Anchor reagent — fix this amount, scale everything else Substrate concentration · M

Amount r Unit

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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	9.09	0.983	0.95
Phthalimide 85-41-6 · C8H5NO2	1.1	10.00	1.471	—

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	10.00	2.623	2.43
2446-83-5 2446-83-5 · C8H14N2O4 density unavailable — volume not calculable.	1.1	10.00	2.022	—

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	—	482.47	34.791	39.09

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 density unavailable — volume not calculable.	1.0	9.09	2.157	—

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: 2.16 g (9.09 mmol)
Expected isolated · 70–90 % yield: 1.51 – 1.94 g

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