Lithium Chloride → ethyl 3-[(4S,5S)-3-benzyloxycarbonyl-2,2-dimethyl-4-isobutyloxazolidin-5-yl]-2-isopropyl-2-propenoate

Participants

Reaction Steps

123 mg of lithium chloride was suspended in 10 ml of dry tetrahydrofuran under an argon atmosphere, and 0.69 ml of ethyl 2-diethylphosphono-3-methylbutanoate was added thereto under stirring. Then, 2.7 ml of a 20% dry tetrahydrofuran solution of diazabicycloundecene was added thereto and stirred for 10 minutes at room temperature. A solution prepared by dissolving 773 mg of (4S,5R)-3-benzyloxycarbonyl-2,2-dimethyl-5-formyl-4-isobutyloxazolidine in dry tetrahydrofuran was gradually dropwise added thereto, and the mixture was stirred overnight at room temperature. The inorganic salt precipitated was filtered off and the solvent was distilled off under reduced pressure. The residue was dissolved in 300 ml of benzene, washed with water and dried oer anhydrous magnesium sulfate. The solvent was distilled off under reduced pressure, and the residue was purified by silica gel column chromatography (32 g of Kiesel gel 60) by using a mixture of n-hexane/ethyl acetate (10/1) to obtain 623 mg of ethyl 3-[(4S,5S)-3-benzyloxycarbonyl-2,2-dimethyl-4-isobutyloxazolidin-5-yl]-2-isopropyl-2-propenoate as a colorless oily substance.

Provenance & Evidence