1,2-Dibromoethane → 2-[4,5-Dimethoxy-2-(1-methyl-2-phenyl-ethyl)-phenyl]-4,4-dimethyl-4,5-dihydro-oxazole

関与物質

反応条件

反応手順

To a rapidly stirring suspension of magnesium turnings (1.32 g, 54.5 mol) and in 35 mL tetrahydrofuran (THF) was added 1,2-dibromoethane (0.10 mL) in one portion. 2-bromo-1-phenylpropane (10.86 g, 54.5 mmol) was added at a rate that maintained the internal temperature at 40° C. After 2.5 hours the cloudy suspension was transferred via canula to a solution of 4,4-dimethyl-2-(2,4,5-trimethoxy-phenyl)-4,5-dihydro-oxazole oxazoline (10.013 g, 36.4 mmol) in 50 mL THF. After 18 hours the solution cooled to 0° C. and quenched by the slow addition of 10% NH4Cl. 500 mL H2O was added and the mixture was extracted with ethyl acetate, washed with H2O, and washed with brine. The combined organics were dried over Na2SO4, filtered and concentrated in vacuo to give a crude solid. Purifications via flash chromatography (4:1 hexane/ethyl acetate) afforded 2-[4,5-dimethoxy-2-(1-methyl-2-phenyl-ethyl)-phenyl]-4,4-dimethyl-4,5-dihydro-oxazole as a clear viscous oil (7.833 g, 41%).

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