Total Synthesis of 7‑Hydroxymurrayazolinine, Murrayamine D, and Mahanine via m‑Nitro Group Activated Pyran Annulation

• Published in: Organic letters Vol. 17; no. 10; pp. 2298 - 2301
• Main Authors: Hou, Shujie, Liu, Yong, Kong, Yali, Brown, Milton L
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 15-05-2015
• Subjects: Alkaloids - chemical synthesis; Alkaloids - chemistry; Biological Products - chemical synthesis; Biological Products - chemistry; Carbazoles - chemical synthesis; Carbazoles - chemistry; Catalysis; Heterocyclic Compounds, 4 or More Rings - chemical synthesis; Heterocyclic Compounds, 4 or More Rings - chemistry; Molecular Structure; Nitro Compounds - chemistry; Pyrans - chemistry; Stereoisomerism
• ISSN: 1523-7060; 1523-7052
• DOI: 10.1021/acs.orglett.5b00422

The facile total synthesis of the natural product (±)-mahanine was obtained in eight steps with an overall 52% yield from readily accessible known nitrophenol derivative 6. After a one-step, acid-catalyzed annulation, two additional natural products were formed including 7-hydroxymurrayazolinine, representing its first reported total synthesis. In the whole process, the introduction of the m-nitro group significantly enhanced the key pyran annulation reaction through inductive effects.