- Total Syntheses of Aspidospermidine, N-Methylaspidospermidine, N-Acetylaspidospermidine, and Aspidospermine via a Tandem Cyclization of Tryptamine-Ynamide
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The total syntheses of aspidospermidine, N-methylaspidospermidine, N-acetylaspidospermidine, and aspidospermine were achieved from a common pentacyclic indoline intermediate. The common pentacyclic indoline intermediate was synthesized on a gram scale through a Stork-enamine alkylation of 1H-pyrrolo[2,3-d]carbazole derivatives, which were prepared through a Br?nsted acid-catalyzed tandem cyclization of tryptamine-ynamide. The scalable synthesis of 1H-pyrrolo[2,3-d]carbazole afforded facile access and a practical approach to the Aspidosperma indole alkaloid family.
- Yang, Lu,Huang, Siwen,Huang, Rongkang,Hou, Anbin,Zhang, Sen,Su, Hongwei,Ding, Xiaohong,Lin, Bin,Cheng, Maosheng,Liu, Yongxiang
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p. 6471 - 6476
(2021/08/23)
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- Divergent Asymmetric Total Synthesis of (+)-Vincadifformine, (-)-Quebrachamine, (+)-Aspidospermidine, (-)-Aspidospermine, (-)-Pyrifolidine, and Related Natural Products
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A uniformly strategic total synthesis of Aspidosperma alkaloids (+)-vincadifformine, (-)-quebrachamine, (+)-aspidospermidine, (-)-aspidospermine, (-)-pyrifolidine, and nine others from efficiently constructed tricyclic ketone 13 is reported. Highlights of these divergent and practical syntheses include (i) stereoselective intermolecular [4 + 2] cycloaddition to establish a C-E ring with one all-carbon quaternary stereocenter (C-5) and two bridged contiguous cis-stereocenters (C-12 and C-19), (ii) a Pd/C-catalyzed hydrogenation/deprotection/amidation cascade process to assemble the D ring, and (iii) Fischer indolization to forge the A-B ring.
- Wang, Nengzhong,Du, Shuo,Li, Dong,Jiang, Xuefeng
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p. 3167 - 3170
(2017/06/23)
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- Divergent total syntheses of (-)-aspidospermine and (+)-spegazzinine
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Divergent total syntheses of (+)-spegazzinine (1) and (-)-aspidospermine (2) and their extensions to the synthesis of C19-epi-aspidospermine and C3-epi-spegazzinine are detailed, confirming the relative stereochemistry and establishing the absolute configuration of (+)-spegazzinine. A powerful intramolecular [4 + 2]/[3 + 2] cycloaddition cascade of a 1,3,4-oxadiazole provided the pentacyclic skeleton and all the requisite stereochemistry of the natural products in a single reaction that forms three rings, four C-C bonds, and five stereocenters.
- Lajiness, James P.,Jiang, Wanlong,Boger, Dale L.
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p. 2078 - 2081
(2012/06/18)
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- Highly efficient synthesis of tricyclic amines by a cyclization/ cycloaddition cascade: Total syntheses of aspidospermine, aspidospermidine, and quebrachamine
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(Chemical Equation Presented) Three in one: Three new rings can be made in one pot with complete control of the regio- and stereochemistry by a tandem cyclization/cycloaddition cascade reaction. Treatment of a chloroaldehyde with an amine gives a cyclic azomethine ylide that undergoes intramolecular cycloaddition onto a tethered alkene. The method was applied to the shortest known synthesis of aspidospermine (see scheme).
- Coldham, Iain,Burrell, Adam J. M.,White, Laura E.,Adams, Harry,Oram, Niall
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p. 6159 - 6162
(2008/04/05)
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- Total synthesis of (-)-aspidospermine via diastereoselective ring-closing olefin metathesis
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(Matrix presented) An enantiocontrolled total synthesis of (-)-aspidospermine has been achieved. The key element of the strategy is the diastereoselective construction of the quaternary stereogenic center employing 1,4-asymmetric induction during the ring-closing olefin metathesis.
- Fukuda, Yu-Ichi,Shindo, Mitsuru,Shishido, Kozo
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p. 749 - 751
(2007/10/03)
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