Diisopropylamine → 3-[6-(1,3-dihydro-6-methoxy-4-methoxyethoxymethoxy-7-methyl-3-oxoisobenzofuran-5-yl)-2-(S),4-dimethylhexanoyl)-4-(R)-isopropyl-2-oxazolidinone

Participants

Reaction Conditions

Reaction Steps

A solution of 1.38 molar n-butyllithium in hexane (11.8 ml) was added to diisopropylamine (2.45 ml) in tetrahydrofuran (50 ml) at -10° C. After 20 minutes, the solution was cooled to -78° C., and a solution of (R)-4-isopropyl-3-propionyl-2-oxazolidinone [prepared as described in J. Am. Chem. Soc., 103:2127 (1981)](3.23 g) in tetrahydrofuran (10 ml) was added. After 30 minutes (E) 4-(1,3-dihydro-6-methoxy-4-methoxyethoxymethoxy-7-methyl-3-oxoisobenzofuran-5-yl)-2-methylbut-2-enyl bromide (2.54 g) in tetrahydrofuran (12 ml) was added. The reaction temperature was allowed to reach -10° C. slowly, then maintained at that temperature for 3 hours. The reaction was quenched with 10% aqueous ammonium chloride then extracted with ethyl acetate. The extract was washed with 10% hydrochloric acid, dilute aqueous sodium bicarbonate and water, then dried and evaporated. The residue was chromatographed on silica gel, eluting with 2:1 hexane:acetone, to yield (E) 3-[6-(1,3-dihydro-6-methoxy-4-methoxyethoxymethoxy-7-methyl-3-oxoisobenzofuran-5-yl)-2-(S),4-dimethylhexanoyl)-4-(R)-isopropyl-2-oxazolidinone as an oil.

Provenance & Evidence