4-Bromotoluene → 6-Bromo-1,1-dimethyl-4-p-tolyl-1,2-dihydronaphthalene

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Reaction Steps

To a mixture of Mg metal (650 mg, 27 mmol) in THF (20 mL) was added 4-bromotoluene (5.3 g, 31 mmol) in THF (40 mL). The mixture was stirred for 2 hours at ambient temperature and heated to 70° C. for 30 minutes. After cooling to ambient temperature, 3,4-dihydro-4,4-dimethyl-7-bromo-1(2H)-naphthalenone (Compound A) (2.1 g, 8 mmol), in THF (5 mL) was added and heated to 70° C. for 24 hours. The mixture was cooled to ambient temperature and the reaction was quenched by addition of H2O. The mixture was diluted with ether:ethylacetate (1:1, 100 mL) and washed with saturated NH4Cl (15 mL), water (10 mL) and brine (10 mL). The organic layer was dried with MgSO4. Solvent was removed under reduced pressure to afford the crude product as an oil. The product was dissolved in THF (20 mL). To this solution p-toleune sulfonic acid (pTSA) (35 mg) was added and the mixture was refluxed for 16 hours. The mixture was cooled to ambient temperature, diluted with ethylacetate (160 mL), washed with 10% NaHCO3 (20 mL), brine (20 mL), dried with MgSO4 and the solvent was removed by evaporation. Purification by chromatography on silica gel gave the title compound as a white solid.

Provenance & Evidence