Rearrangements

7 real reactions from the literature: Curtius rearrangement on acid chlorides and anhydrides; Pinacol rearrangement on 1,2-diols; Beckmann on oximes; Hofmann rearrangement on amides; and more. Each scheme shows starting materials, conditions and products, with the yield and reference where the source reports them.

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1. Curtius rearrangement: dodecanoyl chloride (an acid chloride) with 1) NaN3, H2O, acetone; 2) benzene, Δ gives undecyl isocyanate (the isocyanate or amine).

   Curtius rearrangementOrg. Synth. Coll. Vol. 3, p. 846

2. Pinacol rearrangement: pinacol (a 1,2-diol) with H2SO4; Δ gives pinacolone (the methyl ketone).

   Pinacol rearrangementOrg. Synth. Coll. Vol. 1, p. 462

3. Beckmann: cyclohexanone oxime with H2SO4; Δ gives caprolactam (the seven-membered lactam).

   BeckmannOrg. Synth. Coll. Vol. 2, p. 76

4. Hofmann rearrangement: nicotinamide with Br2, 70 °C; aq. NaOH gives 3-aminopyridine (the aniline).

   Hofmann rearrangementOrg. Synth. Coll. Vol. 4, p. 45

5. Schmidt reaction: cyclobutanecarboxylic acid with 1) NaN3, H2SO4; CH3Cl, 50 °C; 2) NaOH, H2O gives cyclobutylamine (the primary amine).

   Schmidt reactionOrg. Synth. Coll. Vol. 5, p. 273

6. Curtius rearrangement: an anhydride with 1) NaN3, H2O / toluene; 2) Δ (Curtius); 3) HCl, H2O; 4) NaOH gives 1-phenylcyclopentylamine (the isocyanate or amine).

   Curtius rearrangementOrg. Synth. Coll. Vol. 6, p. 910

7. Pinacol rearrangement: benzopinacol (a 1,2-diol) with I2, AcOH; Δ gives 1,2,2,2-tetraphenylethanone (the aryl ketone).

   Pinacol rearrangementOrg. Synth. Coll. Vol. 2, p. 73