Potassium Phosphate, Tribasic → tert-butyl 5-{[tert-butyl(dimethyl)silyl]oxy}-2-(2-chloro-3-quinolinyl)-1H-indole-1-carboxylate

Participants

Reaction Conditions

Reaction Steps

A deoxygenated mixture of 1-(tert-butoxycarbonyl)-5-{[tert-butyl (dimethyl)silyl]oxy}-1H-indol-2-ylboronic acid 1-6 (4.10 g, 10.5 mmol, 1 equiv), 2-chloro-3-iodo-quinoline (1-2, 3.64 g, 12.6 mmol, 1.20 equiv), potassium phosphate (6.67 g, 31.4 mmol, 3.00 equiv), and tetrakis(triphenylphosphine)palladium (0.605 g, 0.524 mmol, 0.050 equiv) in dioxane (100 mL) was heated at 90° C. for 20 hours. The reaction mixture was cooled, then partitioned between a mixture of water and ethyl acetate. The organic layer was separated, washed with brine, dried over magnesium sulfate, and concentrated. The residue was purified by flash column chromatography (20% dichloromethane in hexanes, grading to 90% dichloromethane in hexanes) to give tert-butyl 5-{[tert-butyl(dimethyl)silyl]oxy}-2-(2-chloro-3-quinolinyl)-1H-indole-1-carboxylate (1-7) as a tan-colored foam. 1H NMR (400 MD, CDCl3) δ 8.16 (s, 1H), 8.15 (d, 1H, J=9.0 Hz), 8.07 (d, 1H, J=8.2 Hz), 7.86 (d, 1H, J=7.8 Hz), 7.77 (br t, 1H, J=8.4 Hz), 7.60 (br t, 1H, J=8.1 Hz), 7.03 (d, 1H, J=2.4 Hz), 6.92 (dd, 1H, J=9.0, 2.4 Hz), 6.55 (s, 1H), 1.26 (s, 9H), 1.02 (s, 9H), 0.23 (s, 6H).

Provenance & Evidence