Pyridine → N-[(9H-fluoren-9-ylmethoxy)carbonyl]-N,2-dimethylalanyl-N-[(3R,4S,5S)-3-methoxy-5-methyl-1-oxo-1-(pentafluorophenoxy)heptan-4-yl]-N-methyl-L-valinamide

Participants

Reaction Steps

Pentafluorophenyl 3,3,3-trifluoropropanoate (2.44 mL, 13.4 mmol, 2.0 eq.) was added to a solution of #128 (4.18 g, 6.70 mmol, 1.0 eq.) in 50 mL of dichloromethane followed by pyridine (1.61 mL, 20.1 mmol, 3.0 eq.). Reaction was allowed to stir at room temperature for -12 hours. Reaction was concentrated in vacuo and the residue was purified by silica chromatography (Gradient: 0%-70% acetone in heptanes) producing #135 (5.2 g, 98%) as a white foam. LC-MS (Protocol Q1): m/z 812.1 [M+Na+] retention time=1.24 minutes.

Provenance & Evidence