A gold-catalyzed cyclization reaction of alkynyl-indoles has been developed for the stereoselective construction of the quaternary carbon center of fused indolines. This reaction efficiently produces fused indolines via diastereoselective 6- cyclization controlled by a bulky TIPS group, followed by nucleophilic attack of the carboxy group on the resulting imine. The lactone moiety of the fused indoline can be reductively cleaved to produce a tricyclic indoline, which could be useful for the synthesis of akuammiline alkaloids.
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http://dx.doi.org/10.1021/acs.joc.3c02142 | DOI Listing |
J Org Chem
January 2025
Chang-Kung Chuang Institute, Shanghai Frontiers Science Center of Molecule Intelligent Syntheses, College of Chemistry and Molecular Engineering, East China Normal University, Shanghai 200062, China.
A new stereoselective [4+2] annulation method for constructing tetracyclic indolines by reacting indoles with bicyclic N-substituted cyclobutanes has been developed. Using Sc(OTf) as a catalyst, a series of tetracyclic indolines with four continued stereogenic carbon centers have been obtained in ≤86% yields as single diastereomers. This reaction offers an accessible way for the rapid construction of the core structures of biologically active natural products like paucidirinine, deethylibophyllidine, and ibophyllidine.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2025
Changchun Institute of Applied Chemistry Chinese Academy of Sciences: Chang Chun Institute of Applied Chemistry Chinese Academy of Sciences, Jilin Province Key Lab of Green Chemistry and Process, CHINA.
A modular approach was developed for the first catalytic asymmetric total syntheses of naturally occurring C30 terpene quinone methides and their non-natural stereoisomers, which feature the presence of an unprecedented spiro[4.4]nonane-containing 6-6-6-5-5-3 hexacyclic skeleton. Resting on a chiral phosphinamide-catalyzed enantioselective reduction of 2,2-disubstituted cyclohexane-1,3-dione, a concise route for the synthesis of enantioenriched 6-6 bicyclic fragment was developed.
View Article and Find Full Text PDFOrg Lett
January 2025
College of Chemistry and Materials Engineering, Wenzhou University, Wenzhou 325035, China.
A Ni-catalyzed protocol for the regioselective and stereoselective three-component fluoroalkylthiolation of alkynes with fluoroalkyl halides and thiosulfonates is presented. This reductive difunctionalization provides an efficient strategy for the rapid construction of fluoroalkyl-incorporated vinylthioethers under mild conditions in moderate to good yields.
View Article and Find Full Text PDFToxins (Basel)
December 2024
Department of Chemistry, University of Ghana, Legon-Accra P.O. Box LG56, Ghana.
Mycolactone is a complex macrolide toxin produced by , the causative agent of Buruli ulcer. The aim of this paper is to review the chemistry, biosynthetic, and synthetic pathways of mycolactone A/B to help develop an understanding of the mode of action of these polyketides as well as their therapeutic potential. The synthetic work has largely been driven by the desire to afford researchers enough (≥100 mg) of the pure toxins for systematic biological studies toward understanding their very high biological activities.
View Article and Find Full Text PDFChem Asian J
December 2024
CSIR National Chemical Laboratory, Center for Materials Characterization, INDIA.
We present a comprehensive account of our efforts directed towards the synthesis of sacubitril, a neprilysin inhibitor used in combination with valsartan and marketed as Entresto™. Our initial approach to the formal synthesis of sacubitril employed a chiral pool strategy, utilizing (S)-pyroglutamic acid as a key building block and Cu(I)-mediated Csp2-Csp3 cross-coupling as a key transformation. Further investigations led to the development of chiral amine transfer (CAT) reagents-based stereoselective synthesis.
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