Reaction #577224

Reaction equation

Methyl bromoacetate

21

2-(6-Hydroxy-3-oxo-3H-xanthen-9-yl)-benzoic acid 2-propenyl ester

K2CO3

phenylsilane

→

22

Yield 62.0%

(6′-hydroxy-3-oxospiro[isobenzofuran-1(3H), 9′-[9H]xanthen]-3′-yl)oxy-acetic acid methyl ester

Yield 62.0%

Solvents

DMF

Conditions

Workup

1. 1
   ConcentrationThe mixture was concentrated
2. 2
   workup.ADDITIONdiluted with ethyl acetate
3. 3
   Washwashed with 10% NaHCO3, brine
4. 4
   Dryingdried with anhydrous Na2SO4
5. 5
   Otherevaporated
6. 6
   workup.DISSOLUTIONThe residue was dissolved in dry DCM (25 mL)
7. 7
   workup.STIRRINGThe mixture was stirred for 2 h at room temperature
8. 8
   Concentrationconcentrated
9. 9
   OtherThe residue was purified by column chromatography (ethyl acetate/hexane=1:1)

Procedure

Methyl bromoacetate (0.25 mL, 2.65 mmol) was added dropwise to a stirred mixture of 21 (0.33 g, 0.89 mmol) and K2CO3 (0.36 g, 2.65 mmol) in dry DMF (20 mL) under argon. The resulting mixture was stirred for 4 h at 90° C. The mixture was concentrated, diluted with ethyl acetate, washed with 10% NaHCO3, brine, dried with anhydrous Na2SO4, and evaporated. The residue was dissolved in dry DCM (25 mL). Tetrakis(triphenylphosphine) palladium(0) (58 mg, 0.05 mmol) and phenylsilane (1.1 mL, 8.90 mmol) were added. The mixture was stirred for 2 h at room temperature and concentrated. The residue was purified by column chromatography (ethyl acetate/hexane=1:1) to give 22 as a yellow solid (0.22 g, 62%). TLC (ethyl acetate/hexane, 3:1): Rf=0.5. mp 236° C. 1H NMR (CDCl3/CD3OD, 500 MHz) δ 3.76 (s, 3H, CO2CH3), 4.69 (s, 2H, CH2), 6.68 (m, 6H), 7.19 (d, J=7.5 Hz, 1H), 7.66 (t, J=7.5 Hz, 1H), 7.71 (t, J=7.5 Hz, 1H), 8.01 (d, J=7.5 Hz, 1H). 13C NMR (CDCl3/CD3OD, 125 MHz) δ 52.33, 65.18, 101.86, 102.77, 109.84, 111.55, 112.37, 112.52, 124.05, 124.87, 126.67, 129.00, 129.24, 129.80, 135.21, 152.47, 152.56, 152.94, 159.34, 169.21, 170.15, 171.36, 172.03. ESIMS calcd for C23H17O7 [M+H]+ 405.1. Found 405.2.

Source