Diisopropylamine → 2,2-dibutyl-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, 1.56 M 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 nitrogen gas atmospheres. The mixture was stirred at -20°~0° C. for 30 minutes and then warmed to 34° C. rapidly. To the mixture was added iodobutane (1.8 ml) in one portion. The resulting 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 successively with dilute aqueous hydrochloric acid, aqueous sodium bicarbonate solution and brine. The solvent was dried and evaporated in vacuo. The residue was purified by columnchromatography on silica gel (elution by chloroform/n-hexane, 1/10-1/6) to give 2,2-dibutyl-3,4-dihydro-5-methoxy-1 (2H)-naphthalenone (255 mg) as a pale yellow syrup.

Provenance & Evidence