反应详情

Prepared according to general procedure A using tert-butyl 3-(2-hydroxyphenyl)-3-oxopropanoate (18) (289 mg, 1.2 mmol), 4-bromobenzaldehyde (226 mg, 1.2 mmol), 20.0 mL benzene, piperidine (10 μL, 0.1 mmol) and glacial acetic acid (5.6 μL, 0.1 mmol), refluxed for 3 h. Purified via recrystallization from hexanes/CH2Cl2, yielding 278 mg (57%) of clear crystals. mp=98-100° C.; IR (film) 2978.4; 1712.8; 1629.0; 1155.7 cm−1; 1H NMR (500 MHz, CDCl3) δ 11.84 (bs, 1H); 7.78 (s, 1H); 7.52-7.48 (m, 2H); 7.43-7.21 (AA′BB′, 4H); 7.04 (d, J=7.0 Hz, 1H); 6.83 (t, J=7.3 Hz, 1H); 1.41 (s, 9H); 13C NMR (125 MHz, CDCl3) δ 201.3, 163.5, 162.9, 140.8, 137.4, 132.5, 132.3, 131.9, 131.8, 131.6, 125.3, 120.0, 119.7, 118.7, 83.1, 28.1; LRMS (electrospray): Mass calculated for C20H19BrO4, [M]+, 402.1, 404.0. Found [M+23]+, 424.7, 426.8. An NOE difference experiment was conducted for this compound and a positive NOE was seen for the alkene proton when the tert-butyl signal was irradiated and a positive NOE was seen for the tert-butyl signal upon irradiation of the alkene proton. This compound was further characterized by X-ray crystal structure, see S56.

1. customPrepared
2. temperaturerefluxed for 3 h
3. customPurified via recrystallization from hexanes/CH2Cl2