Chromate → 5,6,7,8-Tetrahydro-5,5,8,8-tetramethyl-benz[f]indan-2-one

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Reaction Conditions

Reaction Steps

A round bottom flask fit with a mechanical stirrer, condenser, thermometer, addition funnel, and nitrogen inlet was charged with 5,5,8,8-tetramethyl-5,6,7,8-tetrahydrobenz(f)indane (43.0 g, 0.0.19 mol) and 84 mL glacial acetic acid and heated to 70° C. While stirring chromate (56.7 g, 0.57 mol, Aldrich) was added slowly maintaining the temperature at about 110° C. After complete addition (30 minutes) the reaction was allowed to cool to room temperature for an additional 2½ hours. The reaction was quenched with 5% HCl/ice and extracted with diethyl ether. The combined ether extracts were washed with water and dried over anhydrous magnesium sulfate. Removal of the solvents by rotary evaporation gave 43.0 g of greenish solids which were washed with chilled acetone to give 16.0 g (98% pure by GC) of solids. The acetone wash was concentrated to give 15.0 g of more solids which were washed with hexane to give 8.7 g (79% pure by GC) of solids. The 16.0 g solids from the acetone wash and 8.7 g solids from the hexane wash were combined to give the crude 5,5,8,8-tetramethyl-5,6,7,8-tetrahydrobenz(f)indan-2one (total of 24.7 g). 1HNMR (CDCl3, 500 MHz) 6 7.75 (s, 1H); 7.43 (s, 1H); 3.08 (t, J=3.5 Hz, 2H); 2.66 (t, J=6 Hz, 2H); 1.71 (s, 4H); 1.32 (s, 6H); 1.30 (s, 6H).

Provenance & Evidence