Reaktion #11170

Reaktionsgleichung

LDA

5-methoxy-1H-indole-2-carbaldehyde

9-hydroxy-4-iodopyrrolo[3,4-c]carbazole-1,3(2H,6H)-dione

(2-bromobenzyl)(triphenyl)phosphonium bromide

→

2-[(E)-2-(2-Bromophenyl)ethenyl]-5-methoxy-1H-indole

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.ADDITIONwas added at 0° C.
2. 2
   Sonstigeto give
3. 3
   Sonstige(after crystallisation from CH2Cl2/hexane) the diene (531) as a yellow solid (the pure E isomer) (88%), mp 120–123° C

Vorschrift

The 5-methoxy-1H-indole-2-carbaldehyde (1) was reacted with (2-bromobenzyl)(triphenyl)phosphonium bromide using the procedure described in example 37, except that the aldehyde was added at 0° C., the ratio of LDA:aldehyde was 1.46:1 and the reaction time was 5 h, to give (after crystallisation from CH2Cl2/hexane) the diene (531) as a yellow solid (the pure E isomer) (88%), mp 120–123° C. 1H NMR (CDCl3) δ 8.21 (br s, 1H), 7.66 (dd, J=7.9, 1.5 Hz, 1H), 7.59 (dd, J=8.1, 1.0 Hz, 1H), 7.32 (br t, J=7.1 Hz, 1H), 7.27 (d, J=8.3 Hz, 1H), 7.22 (d, J=16.4 Hz, 1H), 7.12 (td, J=7.6, 1.5 Hz, 1H), 7.05 (d, J=16.4 Hz, 1H), 7.04 (d, J=2.4 Hz, 1H), 6.88 (dd, J=8.8, 2.4 Hz, 1H), 6.59 (d, J=1.7 Hz, 1H), 3.86 (s, 3H). Found: C, 61.97; H, 4.30; N, 4.17. C17H14BrNO requires C, 62.21; H, 4.30; N, 4.27.

Quelle