Total Syntheses of (−)‐Minovincine and (−)‐Aspidofractinine through a Sequence of Cascade Reactions. (3rd June 2020)

• Record Type: Journal Article
• Authors: Varga, Szilárd; Angyal, Péter; Martin, Gábor; Egyed, Orsolya; Holczbauer, Tamás; Soós, Tibor
• Is Part Of: Angewandte Chemie. Volume 132:Number 32(2020)
• Page Start: 13649
• Page End: 13653
• Publication Date: 2020-06-03
• Subjects: alkaloids -- asymmetric catalysis -- biomimetic synthesis -- organocatalysis -- total synthesis; Chemistry -- Periodicals; 540
• DOI: 10.1002/ange.202004769
• Languages: English
• ISSNs: 0044-8249

Abstract

Abstract: We report 8‐step syntheses of (−)‐minovincine and (−)‐aspidofractinine using easily available and inexpensive reagents and catalyst. A key element of the strategy was the utilization of a sequence of cascade reactions to rapidly construct the penta‐ and hexacyclic frameworks. These cascade transformations included organocatalytic Michael‐aldol condensation, a multistep anionic Michael‐SN 2 cascade reaction, and Mannich reaction interrupted Fischer indolization. To streamline the synthetic routes, we also investigated the deliberate use of steric effect to secure various chemo‐ and regioselective transformations. Abstract : Concise syntheses of (−)‐minovincine and (−)‐aspidofractinine were achieved using easily available and inexpensive reagents and catalyst. A key element of the strategy was the use of a sequence of cascade reactions to rapidly construct the penta‐ and hexacyclic frameworks. To streamline the synthetic routes, the steric effect was used to secure various chemo‐ and regioselective transformations.