Tributylphenyltin → HCID 21883525, compound

Participants

Reaction Conditions

Reaction Steps

A mixture of ethyl 6-chloro-8-bromo-2-(trifluoromethyl)-2H-1-benzopyran-3-carboxylate (Example 74, Step 1) (2.0 g, 5.2 mmol), tetrakis(triphenylphosphine)palladium (0) (2.15 g, 1.7 mmol), triphenylphosphine (0.013 g, 0.05 mmol), and tributylphenyltin (1.9 mL, 5.7 mmol) in toluene (60 mL) was heated to 110° C. for 3 days. The reaction mixture was allowed to cool to room temperature and filtered through a plug of silica gel eluting with 25% ethyl acetate in hexanes. The filtrate was concentrated in vacuo and then purified by flash chromatography (silica gel, ethyl acetate-hexanes, 1:9). The fractions containing desired, product were combined and concentrated in vacuo. To remove the remaining tin impurities the mixture was taken up in THF (10 mL) and aqueous ammonium fluoride solution (10 wt %, 20 mL) and stirred at room temperature for 2 hours. The solution was extracted with ethyl acetate. The extracts were combined, dried over MgSO4, filtered, and concentrated in vacuo to afford the ester as an oil (1.30 g, 65%). 1H NMR (CDCl3/300 MHz) 7.67 (s, 1H), 7.47–7.36 (m, 5H), 7.31 (d, 1H, J=2.6 Hz), 7.18 (d, 1H, J=2.4 Hz), 5.69 (q, 1H, J=6.8 Hz), 4.30 (m, 2H), 1.33 (t, 3H, J=7.1 Hz). 19FNMR (CDCl3/282 MHz) d −78.27 (d, J=7.2 Hz). FABLRMS m/z 383 (M+H). ESHRMS m/z 400.0937 (M+NH4, Calc'd 400.0927)

Provenance & Evidence