Diisopropylsilyl ethers were activated with N-bromosuccinimide, and reacted with a fluorous-tagged alcohol, to yield tethered substrates for ring-closing metathesis reactions.
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http://dx.doi.org/10.1039/b804769n | DOI Listing |
J Org Chem
October 2024
Faculty of Pharmacy, Musashino University, 1-1-20 Shinmachi Nishitokyo, Tokyo 202-8585, Japan.
This study demonstrated for the first time that alkenoic thioesters can be effectively used as nucleophiles in ring-closing disulfenylation reactions. Our investigation revealed that the reaction in hexafluoroisopropanol with an electrophilic sulfur reagent significantly enhances the product yield. We gathered experimental and theoretical evidence to support the superiority of thioesters over the traditionally used benzyl sulfide.
View Article and Find Full Text PDFChemistry
June 2024
School of chemical sciences, Indian Association for the Cultivation of Science, Jadavpur, 700032, Kolkata, India.
Cyclohepta[b]indoles, prevalent in natural products and pharmaceuticals, are conventionally accessed via metal or Lewis acid-mediated cycloadditions with prefunctionalized substrates. Our study introduces an innovative sequential catalytic assembly for synthesizing cyclohepta[b]indoles from readily available isatin derivatives. The process involves three catalytic sequences: ring-closing metathesis, catalytic hydrogenation, and acid-catalyzed ring expansion.
View Article and Find Full Text PDFJ Am Chem Soc
March 2024
Department of Chemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada.
Here we report the first total synthesis of the marine macrolide salarin C, a potent anticancer agent, and demonstrate the biomimetic oxidation-Wasserman rearrangement to access salarin A. This synthesis relies on L-proline catalysis to install a chlorohydrin function that masks the sensitive C16-C17 epoxide and potentially mimics the biosynthesis of these compounds where a related chlorohydrin may yield both THF- and epoxide-containing salarins. Additional and key features of the synthesis include (i) macrocycle formation via ring-closing metathesis, (ii) macrocyclic substrate-controlled epoxidation of the C12-C13 allylic alcohol, and (iii) a late-stage Julia-Kocienski olefination to install the side chain.
View Article and Find Full Text PDFOrg Biomol Chem
March 2024
School of Pharmacy, Fudan University, 826 Zhangheng Road, Pudong Zone, Shanghai 201203, China.
A simple and efficient method has been developed for the synthesis of a diverse range of aryl-fused indolizin-3-ones through sequential Au(I)-catalyzed hydrocarboxylation, aminolysis, and cyclization, followed by ruthenium-catalyzed ring-closing metathesis. Moderate to good yields were observed with satisfactory substrate scope and functional group tolerance. The developed protocol represents a practical strategy for the construction of bioactive aryl-fused indolizin-3-ones.
View Article and Find Full Text PDFJ Am Chem Soc
January 2024
Max-Planck-Institut für Kohlenforschung, 45470 Mülheim/Ruhr, Germany.
Archangiumide is the first known macrolide natural product comprising an endocyclic allene. For the ring strain that this linear substructure might entail, it was planned to unveil the allene at a very late stage of the projected total synthesis; in actual fact, this was achieved as the last step of the longest linear sequence by using an otherwise globally deprotected substrate. This unconventional timing was made possible by a gold catalyzed rearrangement of a macrocyclic propargyl benzyl ether derivative that uses a -PMB group as latent hydride source to unveil the signature cycloallene; the protecting group therefore gains a strategic role beyond its mere safeguarding function.
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