A novel TBAI-catalyzed tandem thio-Michael addition/oxidative annulation of allenes and thioamides for the construction of polysubstituted 2-arylthiophenes under a sulfur migration transformation protocol has been developed. The transition-metal-free protocol achieves the oxidative cyclization reaction of thioamides containing electron-rich substituents with allenes to construct polysubstituted thiophenes selectively by controlling oxidation conditions.
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http://dx.doi.org/10.1039/c8ob01835a | DOI Listing |
Transition metal-catalyzed carbocyclization reactions provide a powerful method for the stereoselective assembly of complex, highly substituted (poly)cyclic scaffolds. Although 1,6-enynes are common substrates for these transformations, using polysubstituted alkene derivatives to construct functionalized cyclic products remains challenging due to their significantly lower reactivity. This highlights key developments in stereoselective semi-intramolecular metal-catalyzed [(2+2)+1] and [(2+2)+2] carbocyclizations of 1,6-enynes containing 1,1-disubstituted alkenes, which produce cycloadducts with quaternary stereogenic centers.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
December 2024
Department of Chemistry, Fudan University, 220 Handan Rd., Shanghai, 200433, China.
Atropisomers with multiple stereogenic axes have attracted much attention due to their increasing significance in the fields of natural products, chiral materials, and drug discoveries. However, the catalytic stereoselective construction of axially chiral ring scaffolds with more than two axes on a single benzene ring remains a challenging task. Herein, we present an efficient method for synthesizing triaxially chiral polysubstituted naphthalene scaffolds via sequential Ni(II)-catalyzed Diels-Alder reaction of isobenzofurans and TfOH-promoted dehydrative aromatization reaction.
View Article and Find Full Text PDFOrg Lett
December 2024
Department of Chemistry, College of Sciences, Nanjing Agricultural University, Nanjing 210095, P. R. China.
A series of 3-phosphonyl polysubstituted pyridine were first synthesized by photocatalysis, combining a phosphonyl radical cascade reaction, Boc deprotection, and aromatization. This strategy can avoid the difficulties of activating the C3-H bond on pyridine to synthesize 3-phosphonylpyridine under mild conditions. Furthermore, by constructing different enynes, we can achieve the metal-free modular synthesis of 3-phosphonyl polysubstituted pyridine, which will be transferred into a new type of phosphine ligand.
View Article and Find Full Text PDFOrg Lett
December 2024
State Key Laboratory of Anti-Infective Drug Discovery and Development, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou 510006, China.
A DNA-compatible three-component reaction is disclosed for the synthesis of on-DNA polysubstituted isoxazolidines that serve as privileged core scaffolds in numerous natural products and bioactive molecules. This one-pot approach involves the 1,3-dipolar cycloaddition of DNA-tagged styrenes with diazo compounds and nitrosoarenes in an aqueous solution of KOAc. The reaction demonstrates excellent functional group compatibility, providing a conventional protocol for the construction of a DNA-labeled isoxazolidine library.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
November 2024
School of Chemistry, Dalian University of Technology, Dalian, 116024, China.
Cyclobutanes are prominent structural components in natural products and drug molecules. With the advent of strain-release-driven synthesis, ring-opening reactions of bicyclo[1.1.
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