Reaction Steps
Prepared according to the general procedure using (Z)-4-benzylidene-2-(3,5-bis(trifluoromethyl)phenyl)-1H-imidazol-5(4H)-one and trans-cinnamaldehyde. The unpurified residue was purified by flash chromatography using 15% EtOAc/hexanes to afford 21 as an off-white solid (88 mg, 57%). Analytical data for 21: 1H NMR (500 MHz, CDCl3) δ 9.16 (s, 1H), 8.15 (s, 2H), 7.80 (s, 1H), 7.40-7.26 (m, 6H), 7.15-7.06 (m, 2H), 7.00-6.96 (m, 2H), 4.11 (d, J=6.9 Hz, 1H), 3.63 (ddd, J=10.1, 6.8, 4.6 Hz, 1H), 3.37 (dd, J=14.8, 4.7 Hz, 1H), 2.44 (dd, J=14.8, 10.1 Hz, 1H); 13C NMR (CDCl3, 126 MHz) δ 168.8, 149.4, 139.0, 137.7, 136.8, 132.4 (q, JCF=33.6 Hz), 131.2, 129.2, 129.0, 128.6, 128.4, 127.9, 126.8, 124.6 (d, JCF=4.0 Hz), 122.9 (d, JCF=273.0 Hz), 122.0, 112.1, 47.1, 38.5, 32.7; IR (film) cm−1 1780, 1641, 1618, 1528, 1401, 1361, 1279, 1186, 1133, 896, 730, 697, 682; LRMS (ESI): Mass calcd for [M+H]+ C27H19F6N2O2: 517.1. found 517.4; Enantiomeric ratio was measured by chiral phase HPLC (Chiralcel OD-H; 3% IPA/1% MeOH/hexanes 1.0 mL/min, 210 nm), Rt1 (minor)=17.2, Rt2 (major)=20.9 min; er=99:1.
