Enantioselective Synthesis of the ABC Ring Motif of Norzoanthamine Based on Asymmetric Robinson Annulation Reactions

• Published in: Organic letters Vol. 13; no. 13; pp. 3308 - 3311
• Main Authors: Nguyen, Thong X, Dakanali, Marianna, Trzoss, Lynnie, Theodorakis, Emmanuel A
• Format: Journal Article
• Language: English
• Published: WASHINGTON American Chemical Society 01.07.2011; Amer Chemical Soc
• Subjects: Alkaloids - chemical synthesis; Azepines - chemical synthesis; Biological Products - chemistry; Chemistry; Chemistry, Organic; Heterocyclic Compounds, 4 or More Rings - chemical synthesis; Models, Molecular; Molecular Structure; Physical Sciences; Quinolines - chemical synthesis; Science & Technology; Stereoisomerism; ZOANTHAMINE ALKALOIDS; ANALOGS; STEREOSELECTIVE-SYNTHESIS
• ISSN: 1523-7060; 1523-7052; 1523-7052
• DOI: 10.1021/ol200966z

An enantioselective strategy for the synthesis of tetracyclic motif 5, representing the northern fragment of norzoanthamine, is presented. Key to the strategy is the use of two asymmetric Robinson annulation reactions that produce the tricyclic ABC ring system with excellent stereoselectivity. Further functionalization at the periphery of the C ring produces compound 5 containing six contiguous stereocenters of the natural product.