Diisopropylamine → 2-butyl-3,4-dihydro-5-methoxy-1 (2H)-naphthalenone

Participants

Reaction Conditions

Reaction Steps

To a solution of lithium diisopropylamide prepared from n-butyllithium (4.0 ml, 1.56M solution in n-hexane) and diisopropylamine (0.88 ml) in freshly distillated dimethoxyethane (20 ml) was added dropwise a solution of 3,4-dihydro-5-methoxy-1(2H)-naphthalenone (881 mg) in dimethoxyethane (5 ml) at -20° C. under N2 gas atmosphere. The mixture was stirred at -20°~0° C. for half an hour and then warmed to 34° C. rapidly. To the mixture was added iodobutane (1.8 ml) in one portion. The mixture was refluxed for 50 minutes, allowed to cool to ambient temperature and poured into aqueous saturated sodium bicarbonate solution (50 ml). The separated oil was extracted with ethyl acetate. The organic layer was washed with dilute aqueous hydrochloric acid, aqueous sodium bicarbonate solution, and brine succeedingly. The solvent was dried and evaporated in vacuo. The residue was purified by column chromatography on silica gel (elution by chloroform/n-hexane, 1/10-1/3) to give 2-butyl-3,4-dihydro-5-methoxy-1 (2H)-naphthalenone (309 mg) as a pale yellow oil.

Provenance & Evidence