Isatin → 3-[4-(tert-Butyl-dimethyl-silanyloxy)-3,5-dimethyl-phenyl]-3-hydroxy-1,3-dihydro-indol-2-one

Participants

Reaction Conditions

Reaction Steps

Dissolve (4-bromo-2,6-dimethyl-phenoxy)-tert-butyl-dimethyl-silane (15.77 g, 50 mmol) in anhydrous THF (250 mL) under nitrogen and cool in a dry ice/acetone bath. Add slowly at −75 to −70° C. 1.6M n-butyl lithium in hexane (31.3 mL, 55 mmol). Stir the resulting white precipitate at −75° C. for 30 min. Add isatin (3.68 g, 25 mmol) as a solid while maintaing positive nitrogen pressure. Remove some dry ice and allow the reaction to warm up slowly to −30 to −40° C. over 3 h and then to 15° C. over 1 h. Pour the reaction into NH4Cl solution and wash with EtOAc (2×500 mL, 250 mL). Wash combined organic portions with water (500 mL) and brine (500 mL). Dry (MgSO4), filter and concentrate in vacuo to give 14.8 g of a yellow solid. Triturate in hexane/ether/CH2Cl2, filter and air dry to give 6.0 g (63%) of the title compound as a pale yellow solid. MS (ES): m/z=383 (M−1); 1H NMR(DMSO-d6): δ10.14 (s, 1H), 7.07 (dt, J=1.1 Hz, J=7.6 Hz, 1H), 6.95 (d, J=7.0, 1H), 6.80 (t, J=7.3 Hz, 1H), 6.72 (m, 3H), 6.27 (s, 1H), 1.95 (s, 6H), 0.83 (s, 9H), 0.00 (s, 6H).

Provenance & Evidence