Toluene → 6-Bromo-4,4-dimethyl-2-methylene chroman

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Reaction Steps

A stirred, cooled (ice bath) solution of 6-bromo-4,4-dimethyl-chroman-2-one available in accordance with U.S. Pat. No. 5,399,561 incorporated herein by reference (1 g, 3.92 mmol) in 8 mL of anhydrous tetrahydrofuran was treated with a 0.5 M solution of μ-chloro-μ-methylene-[bis(cyclopentadienyl)titanium]dimethylaluminum (Tebbe reagent) in toluene (8.23 mL, 4.12 mmol). After 10 minutes, the reaction mixture was poured into ice-water mixture containing 50 mL of 1M sodium hydroxide and extracted with hexane. The hexane extract was washed with brine (×1), filtered over a bed of celite and evaporated in vacuo to an oil which was subjected to flash column chromatography over silica gel (230-400 mesh) using hexane as the eluent to afford the title compound (0.74 g, 74%) as a clear oil.

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