Diisopropylethylamine → (S,R)-1-(2-tert-butoxycarbonylamino-2-phenylacetyl)-pyrrolidine-2-carboxylic acid benzyl ester

Participants

Reaction Steps

To a solution of Boc-D-α-phenylglycine (2 mmol), L-proline benzyl ester hydrochloride (2.2 mmol), and DIPEA (5 mmol) in dry dichloromethane (10 mL) was added TBTU (2.2 mmol). The reaction mixture was stirred at room temperature overnight. The mixture was concentrated under vacuum and the residue was passed through a SCX-2 column and further chromatographed to yield compound 2a. 1H NMR (CDCl3, 400 MHz) δ (ppm) 1.40 (s, 9H), 1.76-1.82 (m, 1H), 1.92-2.07 (m, 3H), 3.09-3.15 (m, 1H), 3.70-3.77 (m, 1H), 4.47-4.51 (m, 1H), 5.16 (d, J=12.35 Hz, 1H), 5.23 (d, J=12.35 Hz, 1H), 5.43 (d, J=7.20 Hz, 1H), 6.12 (d, J=7.20 Hz, 1H), 7.27-7.41 (m, 10H); and MS (ESI, EI+) m/z=439 (MH+).

Provenance & Evidence