Hydrochloric Acid → 1-(2,2,4,4-Tetramethyl-3,4-dihydro-2H-1-benzopyran-6-yl)ethan-1-one

Participants

Reaction Conditions

Reaction Steps

A solution of 6-bromo-2,2,4,4-tetramethyl chroman (see U.S. Pat. No. 6,252,090, 0.9 g, 3.34 mmol) in anhydrous tetrahydrofuran (50 mL) was sparged with argon for 5 min. and treated with dichlorobis(triphenylphosphine)palladium(II) (0.117 g, 0.167 mmol) followed by tributyl(1-ethoxyvinyl)tin (2.41 g, 6.7 mmol). The resulting reaction mixture was heated at 80° C. under argon for 18 h. The reaction mixture was then cooled to ambient temperature and treated with 10% aqueous hydrochloric acid (5 mL) and stirred for 30 min. The reaction mixture was then diluted with ethyl acetate and washed with water (×1) and brine (×1). The organic phase was dried over anhydrous sodium sulfate, filtered and evaporated in vacuo to afford a residue that was subjected to flash column chromatography over silica gel (230-400 mesh) using 2-3%% ethyl acetate in hexane as the eluent to afford the title compound as a colorless oil (0.36 g, 46%).

Provenance & Evidence