反应详情

The aldehyde (846) was reacted with (2-methoxy-4-nitrobenzyl) (triphenyl)phosphonium bromide (582) prepared as described in example 432 using the procedure described in method 2, except that the LDA and aldehyde were (sequentially) added at 0° C., the ratio of LDA;aldehyde was 1.5:1 and the reaction time was 5 h, to give (after crystallisation from CH2Cl2/pentane) the diene (583) as an orange solid (the pure E isomer) (63%), mp 156–159° C. 1H NMR (CDCl3) δ 8.23 (br s, 1H), 7.87 (dd, J=8.5, 2.1 Hz, 1H), 7.76 (d, J=2.2 Hz, 1H), 7.68 (d, J=8.6 Hz, 1H), 7.48 (d, J=7.3 Hz, 2H), 7.39 (t, J=7.3 Hz, 2H), 7.32 (t, J=7.2 Hz, 1H), 7.28 (d, J=17.1 Hz, 1H), 7.26 (d, J=8.7 Hz, 1H), 7.20 (d, J=16.7 Hz, 1H), 7.12 (d, J=2.4 Hz, 1H), 6.97 (dd, J=8.7, 2.5 Hz, 1H), 6.63 (br s, 1H), 5.11 (s, 2H), 4.01 (s, 3H). Found: C, 71.69; H, 4.94; N, 7.11. C24H20N2O4 requires C, 71.99; H, 5.03; N, 7.00.

1. customprepared
2. additionadded at 0° C.
3. customto give
4. custom(after crystallisation from CH2Cl2/pentane) the diene (583) as an orange solid (the pure E isomer) (63%), mp 156–159° C