参考文献https://pubs.acs.org/10.1021/acs.oprd.4c00139Supporting Information Synthesis of Enantiopure Fluoropiperidines via Biocatalytic Desymmetrization and Flow Photochemical Decarboxylative Fluorinationop4c00139_si_001 实验操作The mono acid 8 (488 mg, 1.46 mmol) was dissolved in HFP (5 mL) and treated with methanesulfonic acid (0.142 mL, 2.18 mmol) and stirred at rt over 16 hrs. The resulting slurry was diluted with THF (5 mL) and stirred for 10 min to form a solution. Triethylamine (0.811 mL, 5.82 mmol) was then added followed by Boc2O and the resulting mixture stirred for 4 hrs, after which it was partitioned between saturated aqueous NaHCO3 (x2) and ether (x1). The aqueous phase was acidified with NaHSO4 and extracted into ether. The combined organic layers were then washed with brine and dried over MgSO4, filtered and conc. in vacuo to give a residue. The residue was crystallized from EtOAc/heptane to give 13 (147 mg, 36% yield) as a white solid. MS (ES-) m/z 300.1 [M-H]- . A portion of this material was dissolved in hot EtOAc and allowed to cool to rt. After 1 hr., heptane was added and the mixture allowed to evaporate overnight to give 13 (51 mg) as small flat single crystal plates. This was submitted for single X-ray analysis to confirm the expected absolute stereochemistry.
