Benzaldehyde → 4-Methoxycarbonyl-5-phenyl-2-oxazoline

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39/3 mg (0.55 mmole) of (S)-N-methyl-N-[3-(diethylamino) -propyl]-1-[(R)-1',2-bis(diphenylphosphino)ferrocenyl] -ethylamine and 14.1 mg (0.055 mmole) of silver trifluoromethane-sulfonate was stirred in methylene chloride (5.5 ml) at room temperature for 30 minutes, and then, 0.549 g (5.54 mmole) of methyl isocyano-acetate and 0.642 g (6.05 mmole) of benzaldehyde was added thereto and stirred for 20 hours at 25° C. in nitrogen After being distilled under conditions of 110° C./0.3 mmHg, 1.0 g of 4- methoxycarbonyl-5-phenyl-2-oxazoline (trans/cis =87/13) was obtained. Yield: 91%. The trans-form and the cis-form were separated from each other by column chromatography, and the optical purity of the transform was determined by means of 1H NMR spectroscopy with the same shift reagent Eu(dcm)3 as Example 1, which was 51% ee. After acid-hydrolysis with 6N HC1, L-threo-β-phenylserine, which is a known compound, was obtained.

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