Cyclopentanone → Methyl 3-(cyclopentylamino)-2,2-difluoropropanoate

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Reaction Steps

To a round bottom flask was added methyl 3-amino-2,2-difluoropropanoate (570 mg, 3.24 mmol), THF (20 mL), cyclopentanone (0.433 mL, 4.87 mmol), and HOAc (1 mL). To this mixture was added sodium triacetoxyborohydride (1.06 g, 5 mmol) portionwise. The reaction was left to stir overnight. It was then added slowly to a stirring solution of ice, NaHCO3 (sat.), and EtOAc. The aqueous layer was further extracted with EtOAc, the organic extracts combined, dried over MgSO4, filtered and concentrated to yield methyl 3-(cyclopentylamino)-2,2-difluoropropanoate as clear syrup (400 mg, 60%). 1H NMR (400 MHz, DMSO-d6) δ ppm 1.30 (td, J=13, 6 Hz, 2 H) 1.43 (d, J=8 Hz, 1 H) 1.47-1.70 (m, 4 H) 1.77 (dt, J=12, 6 Hz, 2 H) 3.12 (t, J=6 Hz, 1 H) 3.19 (t, J=14 Hz, 2 H) 3.88 (s, 3 H).

Provenance & Evidence