Tetrahydrofuran → 5-Chloro-9-isopropylidene-1,4-dihydro-1,4-methano-naphthalene

Beteiligte Stoffe

Reaktionsschritte

A solution of 2-bromo-1,3-dichlorobenzene (22.59 g, 0.1 mol) in dry toluene (100 ml) under a nitrogen atmosphere was reacted at −8 to −15° C. with 2M isopropylmagnesium chloride in tetrahydrofuran (50 ml, 0.1 mol) for 1 hour. Subsequent addition of 6,6-dimethylfulvene (13.03 g, assay 97.8%, 0.12 mol) at 0° C. was followed by heating to reflux temperature for 10 hours. Aqueous work up with saturated aqueous ammonium chloride and ethyl acetate extraction followed by washings with brine and water and drying over sodium sulphate gave the crude material which was purified by chromatography on silica gel in hexane to give the desired product (19.03 g, assay 95.2% by g.l.c., 83.6% yield) as a yellow solid. This reaction is also disclosed in WO 2007/068417.

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