Octet / Reactions
Pinacol Rearrangement
Pinacol Rearrangement (Rearrangement.) Converts CC(O)(C)C(O)(C)C to CC(=O)C(C)(C)C using H₂SO₄, H₃PO₄. Conditions: Acidic conditions, heat.
Rearrangement
Reaction details
Name
Pinacol Rearrangement
Type
Rearrangement
Starting Material
CC(O)(C)C(O)(C)C
Product
CC(=O)C(C)(C)C
Reagents
H₂SO₄
H₃PO₄
Conditions
Acidic conditions, heat
Mechanism
- Smiles
CC(O)(C)C(O)(C)C
- Description
Pinacol: 1,2-diol (vic-diol)
- Smiles
CC(O)(C)C(O)(C)C
- Description
Protonation of one OH, water leaves → carbocation
- Smiles
CC(=O)C(C)(C)C
- Description
1,2-methyl shift gives more stable cation, then deprotonation → pinacolone
Tips
1,2-Diol → Ketone (or aldehyde)
Migration to carbocation center
More substituted group usually migrates
Related: semipinacol rearrangement
This is one row of the Reaction roadmap sheet - print all 83 reactions on one page.