Potassium Hydroxide → 3a-butyl-7-methoxy-3,3a,4,5-tetrahydro-2H-cyclopenta[a]naphthalen-2-one

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Reaction Steps

A solution of crude 2-butyl-6-methoxy-2-(2-oxopropyl)-3,4-dihydro-1(2H)-naphthalenone (888 mg, ˜3 mmol) in EtOH (15 mL) was treated with freshly prepared 2N KOH in EtOH (1.5 mL, 3 mmol). The resulting solution was placed under a N2 atmosphere and heated at reflux for 17 hours. After cooling, the mixture was diluted with water (100 mL) and extracted with EtOAc (3×100 mL). The extracts were washed with brine, dried over MgSO4, filtered, and concentrated under vacuum. The residue was purified by Biotage™ (Charlottesville, Va.) flash chromatography on a 40S (4×7 cm) silica gel column, eluting with 1000 mL portions of 19:1 and 10:1 hexane-EtOAc. The product-containing fractions were evaporated under vacuum to provide 3a-butyl-7-methoxy-3,3a,4,5-tetrahydro-2H-cyclopenta[a]naphthalen-2-one as an oil.

Provenance & Evidence