反应详情

Prepared according to general procedure A using tert-butyl 3-(2-hydroxyphenyl)-3-oxopropanoate (18) (618 mg, 2.6 mmol), benzaldehyde (265 μL, 2.6 mmol), 12.0 mL benzene, piperidine (13 μL, 0.13 mmol) and glacial acetic acid (7.5 μL, 0.13 mmol), refluxed for 2 h. Purified via recrystallization from hexanes/CH2Cl2, yielding 708 mg (83%) of 5 as clear crystals. mp=109-110° C.; IR (film) 2978.4; 1737.4; 1692.4; 1643.3; 1145.8 cm−1; 1H NMR (500 MHz, CDCl3) δ 11.92 (bs, 1H), 7.86 (s, 1H), 7.55 (d, J=8.0 Hz, 1H), 7.49 (t, J=8.4 Hz), 1H, 7.37-7.28 (m, 5H), 7.04 (d, J=8.4 Hz. 1H), 6.83 (t, J=7.3 Hz, 1H), 1.42 (s, 9H); 13C NMR (125 MHz, CDCl3) δ 201.6, 163.8, 162.8, 142.3, 137.2, 133.0, 131.9, 131.6, 130.7, 130.3, 129.1, 120.2, 119.6, 118.5, 82.8, 28.1; LRMS (electrospray): Mass calculated for C20H20O4, [M]+, 324.13. Found [M+23]+, 347.3. 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.

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