tert-Butyldimethylsilyl chloride → 2-(2-Benzyloxycarbonylamino-ethyl)-4-(tert-butyl-dimethyl-silanyloxy)-2,5-dihydro-pyrrole-1-carboxylic acid tert-butyl ester

関与物質

反応条件

反応手順

To a pre-cooled (−78° C.) solution containing 6 (400 mg, 1.10 mmol) in THF (10 mL) was added 1M NaHMDS/THF (2.43 mL) in a dropwise fashion. After 45 min, a solution containing TBSCl (348 mg, 2.31 mmol) in THF (5 mL) was added to the heterogeneous reaction mixture. After 30 min, the homogeneous reaction mixture was quenched with saturated aqueous NH4Cl. The solution was diluted with EtOAc and the layers were separated. The organic phase was washed with brine then dried over anhydrous Na2SO4, filtered, and concentrated. The crude product was purified by flash silica gel chromatography (4:1 hexanes/EtOAc) to afford 440 mg (83%) of 7 as a white foam. 1H NMR (CDCl3, 300 MHz), mixture of rotomers: δ7.26 (m, 5H), 5.87 (m, 0.25H), 5.70 (m, 0.25H), 5.48 (m, 0.5H), (app dd, J=16.4, 12.8 Hz, 2H), 4.92 (m, 0.3H), 4.55 (br s, 0.7H), 4.49 (m, 0.7H), 4.39 (m, 0.3H), 3.99 (m, 0.2H), 3.92 (m, 0.4H), 3.86 (br s, 0.4H), 3.76 (m, 1H), 3.28 (m, 0.5H), 3.13 (m, 0.5H), 3.03 (m, 0.5H), 2.92 (m, 0.5H), 1.78 (m, 1H), 1.64 (m, 1H), 1.38 (s, 9H), 0.85 (s, 9H), 0.11 (s, 6H) ppm. Mass spectrum, m/z [499.2] (M+Na)+.

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