Sodium Azide → N-(benzenesulfonyl)-trans-4-azidoproline, methyl ester

Participants

Reaction Conditions

Reaction Steps

In a 50 mL flask were combined 16 (0.60 g, 1.65 mmol) and 1.07 g (16.5 mmol, 10 equiv.) of sodium azide (Aldrich) in 10 mL of anhydrous DMF. The colorless solution was heated at −60° C. under a CaCl2 drying tube overnight, then allowed to cool and filtered. The flask and filter solids were washed with EtOAc, and the filtrate concentrated to dryness. The white residue was dissolved in EtOAc, washed twice with water, then brine, dried (MgSO4), filtered, and concentrated to give a pale yellow, waxy solid. This was recrystallized from EtOAc/hexanes to give 0.43 g (1.39 mmol, 85%) of 17 as fine white needles. 1H-NMR (400 MHz, CDCl3, δ ppm) 7.86 (dt, J=1 Hz, 8 Hz, 2H), 7.61 (tt, J=1 Hz, 8 Hz, 1H), 7.54 (tt, J=1Hz, 8 Hz, 2 H), 4.29 (t, J=8 Hz, 1H), 4.18 (m, 1H), 3.74 (s, 3H), 3.69 (q, J=5 Hz, 1H), 3.41 (dd, J=3 Hz, 11 Hz, 1H), 2.17 (m, 2H); 13C-NMR (400 MHz, CDCl3, 6 ppm) 179.46, 145.01, 140.85, 136.81, 135.14, 67.03, 66.97, 60.71, 60.37, 44.03; m/z: 311 (M+1)+. The trans-stereochemistry was confirmed by X-ray crystal structure.

Provenance & Evidence