(S)-2-((tert-butoxycarbonyl)amino)-3,3-bis(4-fluorophenyl)propanoic acid → tert-butyl (2S,5S)-2-[(2-{[N-(tert-butoxycarbonyl)-4-fluoro-beta-(4-fluorophenyl)-L-phenylalanyl]amino}-6-fluorophenoxy)methyl]-5-({[tert-butyl(dimethyl)silyl]oxy}methyl)morpholine-4-carboxylate

Participants

Reaction Conditions

Reaction Steps

Phosphorus (V) oxychloride (118 μl, 1.262 mmol) was added to a solution of tert-butyl (2S,5S)-2-[(2-amino-6-fluorophenoxy)methyl]-5-({[tert-butyl(dimethyl)silyl]oxy}methyl)morpholine-4-carboxylate (540 mg, 1.147 mmol) and N-(tert-butoxycarbonyl)-4-fluoro-β-(4-fluorophenyl)-L-phenylalanine (433 mg, 1.147 mmol) in pyridine (5.74 mL) at −15° C. The reaction was stirred for 30 minutes then warmed to 0° C. and stirred for another 1.5 hours. LC/MS at this time only shows pyridine and desired product. The reaction was quenched with a saturated aqueous solution of KH2PO4 and the mixture was extracted with ethyl acetate (3×50 mL). The combined organic fractions were dried over MgSO4, filtered and the solvent was evaporated under reduced pressure to afford the title compound (977 mg, 1.106 mmol, 96% yield) as an off-white foam, MS (ESI): m/z=730.51 (M+H-boc). 94% pure by LC/MS. The material was taken on crude to the next step.

Provenance & Evidence