Chlorotrimethylsilane → 5-Bromo-3,3-dimethyltetrahydro-4H-pyran-4-one

Participants

Reaction Conditions

Reaction Steps

A solution of lithium diisopropylamine (2.0 M in heptanes/THF/ethylbenzene) (2.5 ml, 5.1 mmol) diluted with THF (10 mL) under argon was cooled to −78° C. Chlorotrimethylsilane (2.5 mL, 19.5 mmol) was added followed by 3,3-dimethyldihydro-2H-pyran-4(3H)-one (compound 449.1, 500 mg, 3.9 mmol) in THF (5 mL) and triethylamine (8.0 mL, 57 mmol). The resulting mixture was stirred at −78° C. for 5 minutes and then quenched with saturated NaHCO3 (20 mL). The mixture was extracted with ether (30 mL) and the organics was washed with 1M citric acid (50 mL), dried (K2CO3), filtered and concentrated in vacuo. The residue was dissolved in THF (5 mL) and cooled to 0° C. N-Bromosuccinimide (694 mg, 3.9 mmol) was added and the resulting mixture was stirred at room temperature for 2 hrs and then quenched with saturated NaHCO3 (10 mL). The mixture was extracted with ether (2×20 mL) and the organics was washed with brine, dried (MgSO4), filtered and concentrated in vacuo. The residue was purified by silica gel chromatography (8% ethyl acetate in hexane) to yield the title compound as an oil (150 mg, 18%).

Provenance & Evidence