Stereoselective synthesis of (−)-desethyleburnamonine, (−)-vindeburnol and (−)-3-epitacamonine: observation of a substrate dependent diastereoselectivity reversal of an aldol reactionElectronic supplementary information (ESI) available: NMR, HPLC and X-ray spectra of compounds, HPLC and X-ray data. CCDC 1424170-1424172. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c6ob01438k

• Main Authors: Mondal, Pravat, Argade, Narshinha P
• Format: Article
• Language: English
• ISSN: 1477-0520; 1477-0539
• DOI: 10.1039/c6ob01438k

Starting from (−)-acetoxyglutarimide, the enantioselective multistep synthesis of (−)-desethyleburnamonine, (−)-vindeburnol and (−)-3-epitacamonine has been demonstrated via a common hydroxyl-lactam intermediate with very good overall yields. The acetoxy function from (−)-acetoxyglutarimide was initially used as a handle to induce enantioselectivity and then as a latent source of the ketone carbonyl group. Most importantly, substrate dependent reversal of the diastereoselectivity in ester aldol reactions of hexahydroindolo[2,3- a ]quinolizinones has been reported. (−)-Acetoxyglutarimide was used for synthesis of target compounds wherein an acetoxy group induced enantioselectivity and functioned as a source of ketones.