N-Fluorobenzenesulfonimide → Tert-butyl((3aR,4R,6aR)-5-fluoro-2,2-dimethyl-4,6a-dihydro-3aH-cyclopenta[d][1,3]dioxol-4-yloxy)diphenylsilane

関与物質

反応条件

反応手順

Tert-butyl((3aR,4R,6aR)-5-iodo-2,2-dimethyl-4,6a-dihydro-3H-cyclopenta[d][1,3]dioxol-4-yloxy)diphenylsilane (5-4) (1.4 g, 2.7 mmol, 1 equiv) was dissolved in dry THF (18 mL) and N-fluorobenzenesulfonimide (1.0 g, 3.2 mmol, 1.2 equiv) was added. The resulting mixture was cooled to −78° C. and BuLi (3.2 mL, 8.0 mmol, 3 equiv, 2.5 M in hexanes) was added dropwise over 10 minutes. The mixture was stirred at the same temperature for 1 hour. Upon disappearance of the starting material, the reaction was quenched with the addition of 20 mL NH4Cl, extracted with EtOAc (3×20 mL), dried over MgSO4, filtered and concentrated. The crude residue was purified by flash chromatography (80 g SiO2, 0-50% EtOAc in hexanes) to yield tert-butyl((3aR,4R,6aR)-5-fluoro-2,2-dimethyl-4,6a-dihydro-3aH-cyclopenta[d][1,3]dioxol-4-yloxy)diphenylsilane (5-5) as a colorless oil. 1H NMR (500 MHz, CDCl3): δ 7.82 (d, J=5 Hz, 2H); 7.75 (d, J=6.5 Hz, 2H); 7.35-7.44 (m, 6H); 5.27 (s, 1H); 4.77 (dd, J=6.0, 2.0 Hz, 1H); 4.39 (t, J=6.0 Hz, 1H); 4.46 (td, J=6.0, 2.0 Hz, 1H); 1.52 (s, 3H); 1.35 (s, 3H); 1.10 (s, 9H).

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