反应详情

To a stirred solution of 4 (2.50 g, 4.45 mmol) in MeOH (125 mL) a catalytic amount of NiCl2×6H2O was added followed by portions of NaBH4 (in total 0.34 g, 8.9 mmol) every 10 min until no starting material was observed on TLC (system). Ac2O (3 mL) was added after 50 min and the reaction mixture was diluted with toluene, filtered through a plug of silica and concentrated. The residue was purified by silica gel chromatography to give 5 (1.95 g, 3.4 mmol, 76%). 13C-NMR (CDCl3) 170.4, 169.7, 137.3, 137.0 remaining aromatic C 128.5-127.7, 75.3, 72.6, 72.4, 72.1, 72.0, 67.1, 61.91, 61.8, 61.8, 61.3, 61.2, 48.8, 48.6, 28.5 (d, J=142 Hz), 23.0, 20.6, 16.3, 16.2, 16.1; 31P-NMR (CDCl3) 29.5.

1. filtrationfiltered through a plug of silica
2. concentrationconcentrated
3. customThe residue was purified by silica gel chromatography