Triphenylphosphine → (3S,4S)-benzyl 3-amino-4-methylpyrrolidine-1-carboxylate

Participants

Reaction Steps

To solution of (+/−)-(cis)-benzyl 3-azido-4-methylpyrrolidine-1-carboxylat (2.00 g, 7.68 mmol) in acetonitrile (30 mL) and water (3 mL) was added triphenylphosphine (2.42 g, 9.22 mmol) in one portion as solid and the resulting mixture was stirred at rt for 30 min then heated to 60° C. overnight. The resulting mixture was concentrated and taken up in diethyl ether (300 mL), extracted with aq 2N HCl (30 mL×4). The combined aqueous washes were washed with diethyl ether, then the aqueous portion was cooled with ice-bath and was made basic by slowly adding 2N aq NaOH to pH>10. The aqueous mixture was extracted with ether (80 mL×4) and the combined ether extracts were washed with brine, dried over magnesium sulfate, filtered and concentrated to dryness to afford the title compound as a tan oil (1.67 g, 7.13 mmol, 93%). HPLC (method B) retention time=1.51 min. LCMS (m+1)=235.2. 1H NMR (400 MHz, METHANOL-d4) δ 7.42-7.32 (m, 4H), 5.14 (s, 2H), 3.65-3′50 (m, 2H), 3.43 (td, J=5.2, 3.4 Hz, 1H), 3.32-3.28 (m, 1H), 3.25-3.14 (m, 1H), 2.33 (dsxt, J=13.7, 7.0 Hz, 1H), 1.07 (dd, J=6.8, 3.3 Hz, 3H).

Provenance & Evidence