Methanol → 6-Bromo-4-tert-butyl-1,1-dimethyl-1,2-dihydronaphthalene

Participants

Reaction Conditions

Reaction Steps

In a flame dried round bottom flask 7-bromo-3,4-dihydro-4,4-dimethylnaphthalen-1(2H)-one (Compound G, 2.0 g, 7.93 mmol) was dissolved in anhydrous THF (50 ml) and 3,4,5,6,-tetrahydro-2(H)-pyrimidinone (DMPU) (11.5 ml, 95.16 mmol) was added, under argon atmosphere. The reaction was then cooled to -20° C. and a solution of t-butyl magnesium chloride (16 ml, 31.7 mmol) (2 M in Et2O) was added dropwise and stirred at -20° C. for 2 h and at ambient temperature for 1 h, under argon atmosphere. The reaction was quenched at 0° C. with saturated ammonium chloride solution (20 ml) and extracted with EtOAc (2×50 ml). The combined extract was washed with water (20 ml), brine (20 ml) and dried over MgSO4. The solvent was evaporated under reduced pressure to afford a yellow oil. To this yellow oil were added MeOH (50 ml) and p-tolylsulfonic acid (100 mg). The resultant reaction solution was heated in an oil bath (60° C.) for 3 h. The reaction was cooled and quenched with water (20 ml), extracted with EtOAc (2×50 ml). The combined extract was washed with saturated NaHCO3 (20 ml), water (20 ml), brine (20 ml), and dried over MgSO4. The solvent was concentrated in vacuo and the title compound was obtained as a colorless oil after purification by flash chromatography (silica, hexane).

Provenance & Evidence