Acetone → 2,6,6-Trimethylfulvene

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Reaction Steps

A 1 liter flask was charged with 400 mL methanol, methylcyclopentadiene (120.0 mL, 1.21 mol), acetone (200 mL, 2.72 mol), and pyrrolidine (40.0 mL, 0.464 mol). After stirring the orange solution for 71 hours, 50 mL of acetic acid were added, followed by 1200 mL H2O and 200 mL diethyl ether. The organic layer was isolated and the aqueous layer was extracted with diethyl ether (5×100 mL). The combined organic layers were extracted with H2O (3×30 mL) and 10% aqueous NaOH (3×30 mL). The organic layer was dried over MgSO4, filtered and rotavapped to give 158.8 grams of a red-orange oil that was subjected to Kugelrohr distillation under high vacuum. The first 15 grams of material that distilled at room temperature was discarded and the product was obtained from the second fraction that distilled at 50° C.: 136.58 grams (94.0%).

Provenance & Evidence