Oxidative Electro-organic Synthesis of Dimeric Hexahydropyrrolo-[2,3-b]indole Alkaloids Involving PCET: Total Synthesis of (±)-Folicanthine

2021 ◽  
Author(s):  
Kundan Shaw ◽  
Sulekha Sharma ◽  
Arindam Khatua ◽  
Amit Paul ◽  
Alakesh Bisai
Keyword(s):  
Total Synthesis ◽  
Organic Synthesis ◽  
Indole Alkaloids ◽  
Oxidative Dimerization

An efficient electrochemical strategy has been developed for the total synthesis of dimeric hexahydropyrrolo[2,3-b]indole alkaloids. In particular, oxidative dimerization of 3-alkyl 2-oxindoles was developed for this study. A detailed CV...

scholarly journals Structural basis of the stereoselective formation of the spirooxindole ring in the biosynthesis of citrinadins

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Zhiwen Liu ◽  
Fanglong Zhao ◽  
Boyang Zhao ◽  
Jie Yang ◽  
Joseph Ferrara ◽  
...  
Keyword(s):  
High Resolution ◽  
Organic Synthesis ◽  
Indole Alkaloids ◽  
Site Directed Mutagenesis ◽  
Structural Basis ◽  
Directed Mutagenesis ◽  
Computational Studies ◽  
X Ray ◽  
Evolutionary Branch ◽  
Catalytic Mechanisms

AbstractPrenylated indole alkaloids featuring spirooxindole rings possess a 3R or 3S carbon stereocenter, which determines the bioactivities of these compounds. Despite the stereoselective advantages of spirooxindole biosynthesis compared with those of organic synthesis, the biocatalytic mechanism for controlling the 3R or 3S-spirooxindole formation has been elusive. Here, we report an oxygenase/semipinacolase CtdE that specifies the 3S-spirooxindole construction in the biosynthesis of 21R-citrinadin A. High-resolution X-ray crystal structures of CtdE with the substrate and cofactor, together with site-directed mutagenesis and computational studies, illustrate the catalytic mechanisms for the possible β-face epoxidation followed by a regioselective collapse of the epoxide intermediate, which triggers semipinacol rearrangement to form the 3S-spirooxindole. Comparing CtdE with PhqK, which catalyzes the formation of the 3R-spirooxindole, we reveal an evolutionary branch of CtdE in specific 3S spirocyclization. Our study provides deeper insights into the stereoselective catalytic machinery, which is important for the biocatalysis design to synthesize spirooxindole pharmaceuticals.

Recent advances in hapalindole-type cyanobacterial alkaloids: biosynthesis, synthesis, and biological activity

2021 ◽  
Author(s):  
Robert M. Hohlman ◽  
David H. Sherman
Keyword(s):  
Biological Activity ◽  
Total Synthesis ◽  
Indole Alkaloids ◽  
Recent Advances

This review covers isolation, biological activity, an overview of total synthesis efforts and recent biosynthetic discoveries related to hapalindole-type indole alkaloids.

scholarly journals The chemistry of mavacurane alkaloids: a rich source of bis-indole alkaloids

2021 ◽  
Author(s):  
Audrey Mauger ◽  
Maxime Jarret ◽  
Cyrille Kouklovsky ◽  
Erwan Poupon ◽  
Laurent Evanno ◽  
...  
Keyword(s):  
Total Synthesis ◽  
Indole Alkaloids ◽  
Rich Source ◽  
Monoterpene Indole Alkaloids

This review presents the chemistry of mavacuranes, a subfamily of the monoterpene indole alkaloids, from their isolation, biosynthesis, total synthesis to their tendency to assemble with other partners to form intricate bis-indole alkaloids.

Chiral acetylenic sulfoxides in organic synthesis: Secondary amine cyclization and total synthesis of (S)-(−)-carnegine

1995 ◽  
Vol 36 (5) ◽  
pp. 715-718 ◽  
Author(s):  
Winghong Chan ◽  
Albert W.M. Lee ◽  
Lasheng Jiang
Keyword(s):  
Total Synthesis ◽  
Organic Synthesis ◽  
Secondary Amine

Total Synthesis of (−)-Calycanthine via Iron-Catalyzed Stereoselective Oxidative Dimerization

2021 ◽  
Author(s):  
Leiyang Bai ◽  
Yinhao Ma ◽  
Xuefeng Jiang
Keyword(s):  
Total Synthesis ◽  
Oxidative Dimerization

ChemInform Abstract: Total Synthesis of the Indole Alkaloids Henrycinol A (Ia) and B (Ib).

ChemInform ◽  
2014 ◽  
Vol 45 (51) ◽  
pp. no-no
Author(s):  
Kavirayani R. Prasad ◽  
John Eugene Nidhiry ◽  
Makuteswaran Sridharan
Keyword(s):  
Total Synthesis ◽  
Indole Alkaloids

scholarly journals Bioinspired Oxidative Cyclization of the Geissoschizine Skeleton for the Enantioselective Total Synthesis of Mavacuran Alkaloids

2019 ◽  
Author(s):  
Maxime Jarret ◽  
Victor Turpin ◽  
Aurélien Tap ◽  
Jean-Francois Gallard ◽  
Cyrille Kouklovsky ◽  
...  
Keyword(s):  
Total Synthesis ◽  
Oxidative Coupling ◽  
Indole Alkaloids ◽  
Oxidative Cyclization ◽  
Total Syntheses ◽  
Enantioselective Total Synthesis ◽  
Biosynthetic Precursor ◽  
Monoterpene Indole Alkaloids ◽  
Coupling Approach

We report the enantioselective total syntheses of mavacurans alkaloids, (+)-taberdivarine H, (+)-16-hydoxymethyl-pleiocarpamine, (+)-16-epi-pleiocarpamine, and their postulated biosynthetic precursor 16-formyl-pleiocarpamine. This family of monoterpene indole alkaloids is a target of choice since some of its members are subunits of intricate bisindole alkaloids such as bipleiophylline. Inspired by the biosynthetic hypothesis, we explored an oxidative coupling approach from the geissoschizine framework to form the N1-C16 bond. Quaternization of the aliphatic nitrogen was key to achieve the oxidative coupling induced by KHMDS/I<sub>2 </sub>since<sub> </sub>it hides the nucleophilicity of the aliphatic nitrogen and locks the required cis conformation.

scholarly journals Total Synthesis of (+)-Spiroindimicin A via Asymmetric Palladium-Catalyzed Spirocyclization

2021 ◽  
Author(s):  
Zhen Zhang ◽  
Sneha Ray ◽  
Leah Imlay ◽  
Lauren Callaghan ◽  
Hanspeter Niederstrasser ◽  
...  
Keyword(s):  
Total Synthesis ◽  
Human Health ◽  
Neglected Tropical Diseases ◽  
Indole Alkaloids ◽  
Sleeping Sickness ◽  
Tropical Diseases ◽  
African Sleeping Sickness ◽  
Palladium Catalyzed ◽  
Natural Precursor

<p>The spiroindimicins are a unique class of chlorinated indole alkaloids characterized by three heteroaromatic rings structured around a congested spirocyclic stereocenter. Here, we report the first total synthesis of (+)-spiroindimicin A, which bears a challenging C-3’/C-5’’-linked spiroindolenine. We detail our initial efforts to effect a biomimetic oxidative spirocyclization from its proposed natural precursor, lynamicin D, and describe how these studies shaped our final abiotic 9-step solution to this complex alkaloid built around a key asymmetric Pd-catalyzed spirocyclization. Scalable access to spiroindimicins A, H, and their congeners has enabled discovery of their activity against several parasites relevant to human health, providing potential starting points for new therapeutics for the neglected tropical diseases leishmaniasis and African sleeping sickness.</p>

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