Ethyl Acetate → 6-Bromo-3 4-dihydro-4,4-dimethyl-8-vinylspiro[2H-1-benzopyran-2,1'-cyclopropane]

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Following general procedure N and using A solution of methylidene triphenyl phosphorane [generated from methyl triphenylphosphonium bromide (7 g, 20 mmol) and 1.6M solution of n-butyl lithium in hexanes (11.8 mL, 19 mmol)], 6-bromo-8-carbonyl-3,4-dihydro-4,4-dimethylspiro[2H-1-benzopyran-2,1′-cyclopropane] (Intermediate 40, 2.06 g, 7 mmol) followed by flash column chromatography over silica gel (230-400 mesh) using 1-2% ethyl acetate in hexane as the eluent, the title compound was obtained as a clear oil (1.36 g, 66%).

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