Stereo-specific synthesis of hydroanthracene-dicarboximides

Compound 3, N-((1S)-1-cyclohexylethyl)-9,10-dihydro-9,10-ethanoanthracene-(11S,12S)-dicarboximide-1,2,3,4-octahydro, was obtained by ruthenium-assisted hydrogenation of the hydroanthracene-dicarboximide 2 under mild conditions (3 bar H2 and room temperature). In contrast to other related compounds, dicarboximides 2 and 3 were stereo-selectively obtained, confirmed by both solid state (X-ray diffraction) and solution (NMR). This selectivity denoted a hindered rotation around the N–CH axis together with the aromatic hydrogen bond acceptor behaviour of the hydroanthracene skeleton towards a methylene of the cyclohexyl group of the imide moiety. In addition, the nature of the metallic species involved in the hydrogenation process was also investigated.

Only one conformer for hydroanthracene-dicarboximides has been isolated due to an hindered rotation around the N–CH axis together with a strong intramolecular CH/π interaction.Figure optionsDownload as PowerPoint slide