Triphenylphosphine → 5-Ethoxycarbonylmethylene-7-fluoro-1-oxo-1,3,4,5-tetrahydro-azepino[3,4-b]indole-2,10-dicarboxylic acid di-tert-butyl ester

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Reaction Steps

A suspension of triphenylphosphine (3.36 g, 12.8 mmol), Pd(OAc)2 (1.44 g, 6.40 mmol) and Ag2CO3 (3.53 g, 12.8 mmol) in anhydrous THF (100 mL) is stirred at room temperature for 15 minutes. A solution of 2-[tert-butoxycarbonyl-(4-ethoxycarbonyl-but-3-enyl)-aminocarbonyl]-5-fluoro-3-iodo-indole-1-carboxylic acid tert-butyl ester (4.03 g, 6.40 mmol), prepared as in reference 15, in THF (10 mL) is added to the above prepared suspension. The mixture is heated at 60° C. for 16 hours. The inorganic precipitate is removed and the organic layer is concentrated. The residue is purified by silica gel column chromatography and eluted with EtOAc-Hexanes to give the 5-ethoxycarbonylmethylene-7-fluoro-1-oxo-1,3,4,5-tetrahydro-azepino[3,4-b]indole-2,10-dicarboxylic acid di-tert-butyl ester; 1H NMR (CDCl3) δ 1.34 (t, 3H, J=7.6 Hz), 1.57 (s, 9H), 1.60 (s, 9H), 3.46-3.52 (m, 2H), 4.13 (t, 2H, J=4.8 Hz), 4.24 (q, 2H, J=7.6 Hz), 6.30 (t, 1H, J=2.8 Hz), 7.21 (td, 1H, J1=2.8 Hz, J2=9.2 Hz), 7.42 (dd, 1H, J1=2.8 Hz, J2=8.8 Hz), 8.10 (dd, 1H, J1=4.0 Hz, J2=9.2 Hz); m/z [M++Na] 525.0.

Provenance & Evidence