Hydrochloric Acid → ethyl 3-[(4S,5S)-3-benzyloxycarbonyl-2,2-dimethyl-4-isobutyloxazolidine-5-yl]-2-[3-(2-tetrahydropyranyloxy)propyl]-2-propenoate

Participants

Reaction Conditions

Reaction Steps

63.4 mg of lithium chloride was suspended in 5 ml of dry tetrahydrofuran under an argon gas stream. A solution prepared by dissolving 546 mg of ethyl 2-diethylphosphono-5-(2-tetrahydropyranyloxy)heptanoate in 0.6 ml of dry tetrahydrofuran, was added thereto under stirring. The mixture was stirred for five minutes at room temperature, and then 1.4 ml of a 20% dry tetrahydrofuran solution of diazabicycloundecene was added. The mixture was stirred for 10 minutes at room temperature. Then, a solution prepared by dissolving 396 mg of (4S,5R)-3-benzyloxycarbonyl-2,2-dimethyl-5-formyl-4-isobutyloxazolidine in 1.0 ml of dry tetrahydrofuran, was added thereto, and the mixture was stirred overnight at room temperature. The mixture was cooled to 0° C. and then neutralized with 1N hydrochloric acid. Insolubles were filtered off, and the solvent was distilled off under reduced pressure. The residue was dissolved in 20 ml of ethyl acetate and washed with water. The aqueous layer was further extracted twice with 15 ml of ethyl acetate. The ethyl acetate layer was dried over anhydrous magnesium sulfate. The solvent was distilled off under reduced pressure, and the residue was purified by silica gel column chromatography (8 g of Kieselgel 60) by using a mixture of hexane/ethyl acetate (10/1) to obtain 556 mg of ethyl 3-[(4S,5S)-3-benzyloxycarbonyl-2,2-dimethyl-4-isobutyloxazolidine- 5-yl]-2-[3-(2-tetrahydropyranyloxy)propyl]-2-propenoate (E/Z (60/40)) as a colorless oily substance.

Provenance & Evidence