Bis(2-bromoethyl) ether → 7-Methoxy-2',3,3',4,5',6'-hexahydro-2H-spiro [naphthalene-1,4'-pyran]-2-one

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Reaction Steps

To the THF (300 ml) solution of 7-methoxy-3,4-dihydro-1H-naphthalen-2-one (Compound A1, 20 g, 0.11 mol), sodium hydride (9.9 g, 3.7 eq.) was added at 0° C. After stirring for 10 min, 1-bromo-2-(2-bromo-ethoxy)-ethane (19 ml, 12 eq.) was added dropwise thereto, and the mixture was stirred at 80° C. for 3 hr. To the reaction solution, saturated aqueous solution of ammonium chloride was added and the extraction was carried out twice with ethyl acetate. The organic layer was dried over magnesium sulfate. The drying agent was removed by filtration and the residues obtained after concentration under reduced pressure were purified by silica gel column chromatography (ethyl acetate/hexane) to obtain the title compound (white solid, 13 g, 51%).

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