The N-iodosuccinimide-mediated spirocyclization of tryptamine-derived isocyanides to generate spiroindolenines is reported. The products contain both an imine and an imidoyl iodide as flexible handles for follow-up chemistry. Nucleophilic addition typically occurs chemoselectively on the imine moiety with complete diastereoselectivity, providing opportunities for the construction of complex molecular frameworks. The synthetic potential of the method was showcased in the formal total synthesis of (±)-aspidofractinine.
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http://dx.doi.org/10.1002/anie.201809678 | DOI Listing |
J Org Chem
November 2024
Key Laboratory of Organic Synthesis of Jiangsu Province, College of Chemistry, Chemical Engineering and Materials Science & Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University, Suzhou 215123, P. R. China.
A mild approach for synthesizing CF-substituted β-aza-spiroindolines and β-carbolines from tryptamine-derived isocyanides via site-selective radical annulations has been reported. The crucial role of C2 substituents in the selective annulation process has been clarified. The approach shows good generality and practical applicability, highlighting its effectiveness and versatility.
View Article and Find Full Text PDFNat Commun
October 2024
State Key Laboratory of Anti-Infective Drug Discovery and Development, Guangdong Provincial Key Laboratory of Chiral Molecule and Drug Discovery, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, China.
Chem Sci
May 2024
Aachen Maastricht Institute for Biobased Materials (AMIBM), Maastricht University Urmonderbaan 22 6167 RD Geleen The Netherlands
Dearomatization of indoles through a charge transfer complex constitutes a powerful tool for synthesizing three-dimensional constrained structures. However, the implementation of this strategy for the dearomatization of tryptamine-derived isocyanides to generate spirocyclic scaffolds remains underdeveloped. In this work, we have demonstrated the ability of tryptamine-derived isocyanides to form aggregates at higher concentration, enabling a single electron transfer step to generate carbon-based-radical intermediates.
View Article and Find Full Text PDFJ Org Chem
May 2024
Key Laboratory of Organic Synthesis of Jiangsu Province, College of Chemistry, Chemical Engineering and Materials Science, and Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University, Suzhou 215123, People's Republic of China.
In this study, [1+2+2] cyclization of tryptamine-derived isocyanides with 3-ylideneoxindoles was systematically investigated. A series of structurally complex spiro-oxindole derivatives were obtained. Characteristic dynamic covalent chemistry was observed and confirmed by experiments and density functional theory calculation.
View Article and Find Full Text PDFJ Org Chem
December 2023
Department of Chemistry & Pharmaceutical Sciences and Amsterdam Institute for Molecular & Life Science (AIMMS), Vrije Universiteit Amsterdam, De Boelelaan 1108, 1081 HZ Amsterdam, The Netherlands.
Tryptamine-derived isocyanides are valuable building blocks in the construction of spirocyclic indolenines and indolines via dearomatization of the indole moiety. We report the BuN[Fe(CO)NO]-catalyzed carbene transfer of α-diazo esters to 3-(2-isocyanoethyl)indoles, leading to ketenimine intermediates that undergo spontaneous dearomative spirocyclization. The utility of this iron-catalyzed carbene transfer/spirocyclization cascade was demonstrated by its use as a key step in the formal total synthesis of monoterpenoid indole alkaloids (±)-aspidofractinine, (±)-limaspermidine, (±)-aspidospermidine, and (±)-17-demethoxy--acetylcylindrocarine.
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