p-Toluenesulfonic acid → HCID 688882, compound

Participants

Reaction Steps

Prepared according to general procedure using (E)-tert-butyl 2-(2-hydroxy-4-methoxyphenylcarbonyl)-3-phenylprop-2-enoate (71 mg, 0.20 mmol), thiourea catalyst III (14 mg, 0.020 mmol) in 2.0 mL toluene for 42 h at −25° C. and p-toluenesulfonic acid (19 mg, 0.10 mmol) for 18 h. Purification via column chromatography with 10% EtOAc/hexanes afforded 36 mg (71%) of 13 as a white solid in 89% ee. [α]D: +58.5 (EtOH, c=0.5). Analytical data for 13: IR (film) 1683.3, 1608.6, 1442.7, 1258.9 cm−1; 1H NMR (500 MHz, CDCl3) δ 7.89 (d, J=8.5 Hz, 1H), 7.50-7.39 (m, 5H), 6.63 (dd, J=8.8, 2.1 Hz, 1H), 6.52 (d, J=1.5 Hz, 1H), 5.48 (dd, J=13.4, 2.4 Hz, 1H), 3.85 (s, 3H), 3.06 (dd, J=16.8, 13.4 Hz, 1H), 2.85 (dd, J=16.8, 2.8 Hz, 1H); 13C NMR (125 MHz, CDCl3) δ 190.8, 166.4, 163.7, 139.0, 129.1, 129.0 (x2), 126.4, 115.4, 110.5, 101.1, 80.2, 55.9, 44.5; LRMS (electrospray): Exact mass calcd for C16H14O3 [M]+, 254.09. Found [M+1], 255.6.

Provenance & Evidence