Acetic Acid → (2S,4S)4-acetoxy-1-tert-butoxycarbonyl-2-tert-butyldiphenylsilyloxymethypyrrolidine

Participants

Reaction Conditions

Reaction Steps

To a stirred mixture of (2S,4R)-1-tert-butoxycarbonyl-2-tert-butyldiphenylsilyloxymethy-4-hydroxypyrrolidine (21.7 g, 47.6 mmol), acetic acid (3.0 ml, 52.4 mmol) and PPh3 (12.5 g, 52.4 mmol) in THF (330 ml) was added DIAD (9.4 ml, 47.6 mmol) at room temperature under an atmosphere of nitrogen. After 2 h stirring the same temperature, the mixture was heated at 50° C. for 2 h. After cooling to room temperature, the reaction mixture was concentrated in vacuo. The resulting residue was chromatographed on silica gel [1 Kg, n-hexane/EtOAc(5/1)], to give (2S,4S)-4-acetoxy-1-tert-butoxycarbonyl-2-tert-butyldiphenylsilyloxymethypyrrolidine (23.3 g, 99%) as a colorless oil. 1H-NMR (CDCl3) δ1.06 (s, 9H), 1.35 and 1.43 (s, 9H, amide isomers), 1.92 (br, 3H), 2.20-2.45 (m, 2H), 3.31-4.07 (m, 5H), 5.17-5.30 (m, 1H), 7.36-7.44 (m, 6H), 7.65-7.71 (m, 4H).

Provenance & Evidence