m-Chloroperbenzoic acid → Methyl 2-[(4'-methoxy[1,1'-biphenyl]-4-yl)sulfonyl]amino-3-phenylmethoxy-4,5-epoxypentanoate

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Reaction Steps

The methyl 2-[(4′-methoxy[1,1′-biphenyl]-4-yl)sulfonyl]amino-3-phenylmethoxy-4-pentenoate 63d (1.23 g, 2.48 mmol) is dissolved in methylene chloride (9 mL) and sodium bicarbonate (252 mg), in water (4 mL), then the reaction is cooled to 0° C. 3-Chloroperoxybenzoic acid is added slowly and the reaction is stirred for two hours. The substrate is still present so additional 3-chloroperoxybenzoic acid is added (1 g) along with 175 mg sodium bicarbonate and the reaction is stirred overnight. The mixture is diluted with aqueous sodium bicarbonate solution and methylene chloride and the layers are separated. The aqueous layer is washed with ethyl acetate (3 times) and the organic layers are combined and dried under reduced pressure. The resulting material is redissolved in ethyl acetate and washed with dilute sodium bicarbonate solution and then with brine, dried over magnesium sulfate and concentrated in vacuo to a light brown oil (2 g). The crude material is adsorbed onto silica gel and purified over a silica column eluting with hexane:ethyl acetate (8:2) followed with hexane:ethyl acetate (1:1). Product fractions are combined and dried to give the desired product.

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