4-Toluenesulfonyl chloride → (S)-2-((tert-Butoxycarbonyl)amino)-3-phenylpropyl 4-methylbenzenesulfonate

Participants

Reaction Conditions

Reaction Steps

The recovered intermediate (20a) (8.5 g, 33 mmol, 1.0 eq) was dissolved into 70 mL pyridine containing potassium hydroxide (2.1 g, 37 mmol, 1 . 1 eq) and the mixture was chilled in an ice bath. Tosyl chloride (7.1 g, 37 mmol, 1.1 eq) was added and the mixture was stirred at 0° C. for 2 hours then refrigerated overnight. The mixture was filtered and the filtrate was concentrated under reduced pressure. The recovered residue was dissolved into 300 mL EtOAc, washed with 2×200 mL 1M H3PO4, saturated bicarbonate, and saturated aqueous NaCl. The organic was dried over MgSO4 and concentrated under reduced pressure to yield intermediate (20b) (10.3 g) as a pale brown oil.

Provenance & Evidence