p-Toluenesulfonic acid → HCID 46232081, compound

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Reaction Steps

Prepared according to general procedure using (E)-tert-butyl 2-(2-hydroxy-4-methylphenylcarbonyl)-3-phenylprop-2-enoate (51 mg, 0.15 mmol), thiourea catalyst III (10 mg, 0.020 mmol) in 1.5 mL toluene for 6 d at −25° C. and p-toluenesulfonic acid (15 mg, 0.08 mmol) for 9 h. Purification via column chromatography with 10% EtOAc/hexanes afforded 35 mg (97%) of 14 as a white solid in 90% ee. [α]D: +54.8 (EtOH, c=0.52). Analytical data for 14: IR (film) 1688.6, 1616.6, 1295.2, 1242.3 cm−1; 1H NMR (500 MHz, CDCl3) δ 7.83 (d, J=8.4 Hz, 1H), 7.49-7.38 (m, 5H), 6.89-6.87 (m, 2H), 5.46 (dd, J=13.3, 2.7 Hz, 1H), 3.06 (dd, J=16.9, 13.3 Hz, 1H), 2.87 (dd, J=16.9, 2.7 Hz, 1H) 2.34 (s, 3H); 13C NMR (125 MHz, CDCl3) δ 192.0, 161.8, 148.0, 139.1, 129.1, 129.0, 127.2, 126.4, 123.2, 118.9, 118.4, 79.8, 44.9, 22.2; LRMS (electrospray): Exact mass calcd for C16H14O2 [M]+, 238.10. Found [M+1], 239.1.

Provenance & Evidence