4-Nitrophenol → HCID 131734381, compound

Participants

Reaction Steps

To a mixture of Boc-L-phenylalanine (1.33 g, 5 mmol), p-nitrophenol (PNP) (838 mg, 6 mmol) and DIPEA (1.75 ml, 10 mmol) in anhydrous DCM (10 mL) was added HATU (2.28 g, 6 mmol) in one portion under a nitrogen atmosphere. The resulting mixture was stirred at room temperature for 4 h. After aqueous work-up the crude product was purified by flash column chromatography (silica gel, 0-20% EtOAc/hexanes) to give Boc-L-phenylalanine-PNP ester (R-40). To an ice-cooled mixture of R-101 (54 mg, 0.1 mmol) and R-40 (77 mg, 0.2 mmol) in anhydrous THF (2 mL) was added LiHMDS (0.15 mL of 1M solution in THF, 0.15 mmol) dropwise under a nitrogen atmosphere. The resulting mixture was stirred at the same temperature for 2 h. The reaction mixture was quenched with saturated ammonium chloride solution and extracted with DCM. The combined organic extracts were dried over MgSO4, filtered and concentrated. The crude material was purified by flash column chromatography (silica gel, 0-5% MeOH/DCM) to give R-41.

Provenance & Evidence