ORGN 82 |
| Previous work in our groups has shown that the ortho C-H bond of an aromatic imine can be selectively activated by a rhodium(I) catalyst and coupled to a tethered olefin to give the cyclized product. To demonstrate the utility of this methodology, we chose as synthetic targets two biologically active molecules possessing dihydropyrroloindole cores (1 and 2). Conversion of the appropriate indole-3-carboxaldehyde to the corresponding benzyl imine provides the substrate for the key cyclization step, which proceeds via rhodium-catalyzed C-H bond activation. Additionally, 2 contains a stereocenter that can be set during cyclization using chiral nonracemic phosphoramidite ligands, as shown previously by our group. Catalytic decarbonylation and direct indole/maleimide coupling provide access to 2 more efficiently than does the literature-reported sequence.
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Heterocycles, Aromatics, Materials, Devices, Switches, Combinatorial Chemistry, Metal-Mediated Reactions
8:00 PM-10:00 PM, Sunday, 13 March 2005 Convention Center -- Hall D, Poster
Division of Organic Chemistry |
