p-Toluenesulfonic acid → 2H-Pyran-2-one, 6-((1E)-4,4-bis(4-fluorophenyl)-3-(1-methyl-1H-tetrazol-5-yl)-1,3-butadien-1-yl)tetrahydro-4-hydroxy-, (4R,6S)-rel-

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Reaction Steps

Cis-(4R,6S)-6-[4,4-bis(4-fluorophenyl)-3-(1-methyl-1H-tetrazol-5yl)-1,3-butadienyl]-2,2-dimethyl-1,3-dioxane-4-acetic acid (3.7 g, 7.45 mmol) was dissolved in a solution of THF (90 mL) and 0.2N HCl (60 mL) and allowed to stand for 16 hours. The solution was partitioned between ethyl acetate and water. The organic layer was washed with brine (2x), dried (Na2SO4), and concentrated under reduced pressure. The residue was dissolved in dry methylene chloride (60 mL) and stirred for 4 hours in the presence of 1-cyclohexyl-3-(2-morpholinomethyl) carbodiimide metho-p-toluenesulfonate (6.6 g, 15.6 mmol). The solution was concentrated under reduced pressure and the residue was partioned between ethyl acetate and water. The organic layer was dried (Na2SO4) and concentrated under reduced pressure. The residue was purified by chromatography on silica gel (1:1/ethyl acetate:diethyl ether). After recrystallization from ethyl acetate-hexane, 1.33 g (40.1%) of the title compound was obtained as a white solid; m.p.=172°-173° C. [α]D25 =+237.8° (c=2.17, CHCl3).

Provenance & Evidence