Methanol → tert-butyl (6R,7R)-6-(3,4-dichlorophenyl)-7-(1,2,3-trihydroxypropan-2-yl)-1,4-oxazepane-4-carboxylate

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Reaction Steps

Into a solution of tert-butyl (6R,7R)-6-(3,4-dichlorophenyl)-7-(3-hydroxypent-1,4-dien-3-yl)-1,4-oxazepane-4-carboxylate (2.31 g) in methanol (50 ml) was introduced an ozone gas (from ozone developing apparatus) at −78° C. with stirring. When the solution turned pale-blue, introduction was stopped, and a nitrogen gas was introduced instead until the pale-blue color disappeared. Sodium tetrahydroborate (612 mg) was added at −78° C., and the mixture was warmed with stirring to room temperature, and stirred for 10 min. Water was added to quench the reaction, methanol was evaporated under reduced pressure, and the residue was extracted three times with ethyl acetate. The organic layer was washed with brine, and dried over anhydrous sodium sulfate, and the solvent was evaporated. The residue was purified by silica gel column chromatography (eluent; hexane:ethyl acetate (10%-100%)) to give the title compound (800 mg) as a colorless oil.

Provenance & Evidence