(Diethylamino)sulfur trifluoride → Methyl 4-[bis(tert-Butoxy)phosphoryl-fluoromethyl]-N-(benzyloxycarbonyl)-D,L-phenylalaninate

Participants

Reaction Steps

To DAST (0.15 mL, 1.1 mmol) in anhydrous CHCl3 (0.6 mL) at -78° C. is slowly added compound 9 (536 mg, 1.0 mmol) in CHCl3 (2.0 mL). After 10 minutes, the reaction mixture is warmed to ambient temperature and stirred (20 minutes). The mixture is slowly diluted with brine (10 mL) then extracted with CHCl3 (2×10 mL) and the combined extracts dried (MgSO4) and evaporated under reduced pressure to yield crude 20 (629 mg). Purification by silica gel chromatography affords pure 20 as a syrup (295 mg, 55%).

Provenance & Evidence