Tetrabutylammonium Fluoride → 2-(2-Benzyloxycarbonylamino-ethyl)-4-hydroxy-pyrrolidine-1-carboxylic acid tert-butyl ester

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Reaction Conditions

Reaction Steps

A solution containing 4 (5.9 g, 12.5 mmol) in anhydrous THF (100 mL) was cooled to 0° C. TBAF (1M/THF, 14 mL, 14.0 mmol) was added in one portion. After 5 h, the reaction mixture was diluted with EtOAc and washed successively with 1M HCl and brine, dried over anhydrous Na2SO4, filtered, and concentrated. The crude product was purified by flash silica gel chromatography (1:1 to 1:3 hexanes/EtOAc) to afford 4.1 g (91%) of 5. 1H NMR (CDCl3, 300 MHz): δ7.31 (m, 5H), 5.93 (m, 1H), 5.07 (m, 2H), 4.37 (m, 1H), 4.03 (m, 1H) 3.51-3.06 (m, 4H), 2.05 (m, 1H), 1.77 (m, 1H), 1.44 (s, 9H) ppm. Mass spectrum, m/z [365.2] (M+H)+.

Provenance & Evidence