反应详情

The title compound was prepared according to the general procedure from ethyl trans-4-oxo-2-butenoate and trans-N-(4-methoxybenzenesulfonyl)-3-(furan-2-yl)prop-2-en-1-imine using 10 mol % 9 as the catalyst in 71% yield as a yellow solid. [α]D20 (c 1.58, CHCl3)=+125.7; mp=98-100° C.; 1H NMR (400 MHz, CDCl3) δ 7.98 (dd, 2H, J=7.0, 1.9 Hz), 7.12 (d, 2H, J=8.0 Hz), 7.00 (dd, 21-1, J=7.0, 1.9 Hz), 6.87 (d, 1H, J=1.8 Hz), 6.11 (dd, 1H, J=3.2, 1.8 Hz), 5.82 (d, 1H, J=3.2 Hz), 5.51 (dd, 1H, J=8.0, 6.8 Hz), 4.15-4.10 (m, 2H), 3.90 (s, 3H), 3.75 (t, 1H, J=6.7 Hz), 3.45-3.40 (m, 1H), 2.72 (dd, 1H, J=17.3, 6.0 Hz), 2.52 (s, 3H), 2.04 (dd, 1H, J=17.3, 7.7 Hz), 1.22 (t, 3H, J=7.0 Hz); 13C NMR (100 MHz, CDCl3) δ 171.7, 168.7, 164.2, 142.6, 131.4, 129.6, 125.7, 114.1, 110.4, 108.0, 61.0, 56.0, 43.2, 35.1, 31.5, 14.3; IR (thin film) ν 3114, 2982, 2843, 1724, 1595, 1498, 1363, 1263, 1167, 1133, 1092, 1025 cm−1; HRMS (ESI) calcd for C20H21NO7S [M+Na]+ 494.1243, found 494.1265; >99% ee (3S,4S)-isomer as determined by HPLC (AD-H, 9:1 hexanes/i-PrOH), tr (3S,4S)=43.7 min, tr (3R,4R)=37.4 min.