60% |
Stage #1: 2-nitrophenoxyacetic acid With phenylsilane; potassium-t-butoxide; C22H30ClN2RuS2(1+)*Cl(1-) In tetrahydrofuran at 60℃; for 18h; Inert atmosphere;
Stage #2: With water monomer; caesium fluoride In tert-butyl methyl ether at 20℃; for 3h; Inert atmosphere; |
2-(2-Nitro-phenoxy)-ethanol (4f):
To a stirred suspension of (2-nitro-phenoxy)-aceticacid (3f) (500 mg, 2.5105 mmol,1equiv.) in degassed THF (10 V) was added ARP-03 (26.3 mg, 0.050 mmol, 2 mol%)and again degassed for 10 minutes. After 10 minutes of degassing, PhSiH3 (0.94mL, 7.5315 mmol, 3 equiv.) and t-BuOK (1 M in THF) (0.25 mL, 0.2510 mmol, 10mol%) were added dropwise to reaction mixture at RT. The reaction mixture washeated to 60°C and stirred for 18 h. The reaction mixture was then evaporatedto remove volatiles, then suspended in MTBE and stirred with aq. CsF solution(10%, 10 V) for 3 h. The organic layer was then separated and concentrated invacuum to furnish the crude, which was purified by column chromatography on silica gel (eluent:Ethyl acetate / n-hexane = 1/4) to afford 2-(2-nitro-phenoxy)-ethanol (4f) (279 mg, 60%) as a brown oil. 1H NMR (400 MHz, DMSO- d6): 7.90 - 7.75 (m, 1H), 7.65 - 7.55 (m, 1H), 7.45 - 7.30 (m,1H), 7.15 - 7.05 (m, 1H), 4.87 (t, J= 5.6 Hz, 1H), 4.14 (t, J = 4.8 Hz,2H), 3.75 - 3.60 (m, 2H).13C NMR (100 MHz, DEPT - 135, CDCl3): δ 152.38 (C), 140.04 (C),134.52 (CH), 127.80 (CH), 125.94 (CH), 121.04 (CH), 71.44 (CH2),61.04 (CH2).LCMS (EI, m/z) calcd for C8H9NO4[M + Na]: 206.17 Found: 206.1 |