7-Chloro-2-methyl-1H-indene → 2-Methyl-7-phenylindene

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Reaction Steps

A 5 L round bottom flask was equipped with mechanical stirring, a reflux condenser and ice bath. 488.2 g distilled 7-chloro-2-methylindene (2.97 mol) was added, dissolved in 2 L ether and 32.2 g Ni(dpp) (0.059 mol, 2 mol %) slurried in the solution, and stirred to cool to 0°-2° C. 1.05 L of 3.1M phenylmagnesium bromide in ether (3.25 mol, 10% excess) was added slowly from an addition funnel so that the temperature remained below 5° C. Once complete, the ice bath was removed, and the reaction stirred up to room temperature. The reaction was refluxed for 8 hours, and checked for completion by GC. The reaction flask was cooled with an ice bath, and 250 mL water added, then 1 L 10% HCl. The aqueous and organic layers are separated, and the organic layer dried over anhydrous Na2SO4. Ether was distilled, and the residual oil placed on a column of 100 g silica gel. Elution with hexane was performed, the hexane distilled under reduced pressure to a temperature of 90° C. 2-methyl-7-phenylindene (Spaleck compound 13a) was obtained by distillation at <1 mm Hg with a 36 cm Vigreux column at 125° C. A fore-cut containing biphenyl was obtained at 70°-90° C. and discarded. Yield was 507.8 g (2.47 mol) equal to 80%.

Provenance & Evidence