Lithium diisopropylamide → HCID 21980638, compound

Participants

Reaction Steps

The 5-methoxy-1H-indole-2-carbaldehyde (1) was reacted with (2,6-dichloro-4-methoxybenzyl)(triphenyl)phosphonium bromide (521), prepared as described in example 112, using the procedure described in example 37, except that the aldehyde was added at 0° C., the ratio of LDA:aldehyde was 1.37:1 and the reaction time was 5 h, to give (after crystallisation from CH2Cl2/hexane) the diene (522) as a cream solid (the pure E isomer) (70%), mp 128–129° C. 1H NMR (CDCl3) δ 8.17 (br s, 1H), 7.25 (d, J=8.7 Hz, 1H), 7.17 (d, J=16.8 Hz, 1H), 7.04 (d, J=2.4 Hz, 1H), 6.93 (s, 2H), 6.88 (d, J=16.8 Hz, 1H), 6.86 (dd, J=8.7, 2.5 Hz, 1H), 6.57 (br d, J=1.7 Hz, 1H), 3.85 (s, 3H), 3.82 (s, 3H). Found: C, 62.01; H, 4.23; N, 4.21. C18H15Cl2NO2 requires C, 62.09; H, 4.34; N, 4.02.

Provenance & Evidence