A modular, stereoselective route to trisubstituted ()-alkenyl (MIDA)boronates is described, consisting of the radical addition-fragmentation of dithiocarbonates to 2-(MIDA)boronyl-3-(2'-fluoro-pyridyl-6'-oxy)-alkenes. The bulky (MIDA)boronate ensures a highly stereoselective fragmentation that is enhanced by the poor stabilization of the radical adjacent to the tetravalent boron atom. The vinyl boronate precursors are prepared from propargyl alcohols by copper-catalyzed regioselective protoboration of their fluoropyridoxy derivatives, with the fluoropyridine acting as an internal directing group.
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http://dx.doi.org/10.1021/acs.orglett.1c03022 | DOI Listing |
J Org Chem
January 2025
Institute of Chemistry, Technical University of Berlin, Straße des 17. Juni 115, 10623 Berlin, Germany.
Chiral heterocyclic alcohols and amines are frequently used building blocks in the synthesis of fine chemicals and pharmaceuticals. Herein, we report a one-pot photoenzymatic synthesis route for -Boc-3-amino/hydroxy-pyrrolidine and -Boc-4-amino/hydroxy-azepane with up to 90% conversions and >99% enantiomeric excess. The transformation combines a photochemical oxyfunctionalization favored for distal C-H positions with a stereoselective enzymatic transamination or carbonyl reduction step.
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 Sci
December 2024
Department of Chemistry, Korea Advanced Institute of Science & Technology (KAIST) Daejeon 34141 Republic of Korea
Securinega alkaloids, known for their unique structures and neuroplasticity-inducing potential, are promising candidates for treating neurodegenerative diseases such as depression and substance use disorders (SUD). Herein, we delineate the total synthesis of two dimeric Rauhut-Currier (RC) reaction-based securinega alkaloids, (-)-flueggenine A and (-)-15'--flueggenine D. The key step involved a novel reductive Heck dimerization strategy, utilizing a silyl-tethered enone coupling partner to ensure the desired reactivity and stereoselectivity.
View Article and Find Full Text PDFChem Sci
December 2024
National Research Center for Carbohydrate Synthesis, Jiangxi Normal University 99 Ziyang Avenue Nanchang 330022 China
Capitalizing on Hauser annulation and Yu glycosylation, the chemical synthesis of chartreusin-type aromatic polycyclic polyketide glycosides has been investigated, culminating in the successful establishment of chemical approaches toward chartreusin derivatives with intricate chemical structures but promising bioactivities. Based on the chemical synthesis strategy, the first and collective chemical syntheses of chartreusin, D329C, and elsamicins A and B have been accomplished. The chemical strategy was featured by two complementary routes to secure chartarin 10--monosaccharide glycosides, the key intermediates in chartreusin derivative synthesis, as well as the highly stereoselective construction of the difficult glycosidic linkages.
View Article and Find Full Text PDFJ Org Chem
December 2024
School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Queensland 4072, Australia.
l-Guluronic acid is integral to the structures of alginates and to the pathogenesis of . The exploitation of this hexose in both existing and new contexts is, however, limited by its prohibitively high commercial cost. We report on a short and efficient synthetic route to an l-GulA building block from a simple d-mannose thioglycoside.
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