Ethanol heptane → (2S,4R)-Methyl 2-(3,4-difluorobenzyl)-4-(3-oxo-2,3-dihydroisoxazol-5-yl)piperidine-1-carboxylate

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Reaction Steps

Cis-methyl 2-(3,4-difluorobenzyl)-4-(3-oxo-2,3-dihydroisoxazol-5-yl)piperidine-1-carboxylate (1.36 g, 3.87 mmol) was subjected to chiral preparative HPLC (Column: Chiralpak AD (250×20), 5 μm particle size, mobile phase: Heptane/EtOH/FA 90/10/0.2, flow rate 18 mL/min) to yield (2R,4S)-methyl 2-(3,4-difluorobenzyl)-4-(3-oxo-2,3-dihydroisoxazol-5-yl)piperidine-1-carboxylate (550 mg (40%), Chiral purity 98.2% ee, Optical rotation [α]D20=+15.0 (acetonitrile, c=1) and (2S,4R)-methyl 2-(3,4-difluorobenzyl)-4-(3-oxo-2,3-dihydroisoxazol-5-yl)piperidine-1-carboxylate (596 mg, 44%), Chiral purity 99.4% ee, Optical rotation [α]D20=−13.2 (acetonitrile, c=1)

Provenance & Evidence