A metal-free approach for the synthesis of seven-membered N-heterocycles has been developed by the I -promoted intramolecular cross-coupling/annulation of butenyl anilines. This cyclization reaction involves C-H activation and C-C bond formation and exhibits good functional group tolerance. A series of benzo[b]azepine derivatives are obtained in moderate to good yields.
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http://dx.doi.org/10.1002/asia.202100710 | DOI Listing |
Angew Chem Int Ed Engl
January 2025
Cardiff University, School of Chemistry, Park Place, Main Building, CF10 3AT, Cardiff, UNITED KINGDOM OF GREAT BRITAIN AND NORTHERN IRELAND.
Despite the remarkable advancements in hypervalent iodine chemistry, exploration of bromine and chlorine analogues remains in its infancy due to their difficult synthesis. Herein, we introduce six-membered cyclic λ3-bromanes and λ3-chloranes. Through single-crystal X-ray structural analyses and conformational studies, we delineate the crucial bonding patterns pivotal for the thermodynamic stability of these compounds.
View Article and Find Full Text PDFPhotosynth Res
January 2025
Graduate School of Life Sciences, Ritsumeikan University, Kusatsu, Shiga, 525-8577, Japan.
Pheophytin-a derivatives possessing plastoquinone and phylloquinone analogs in the peripheral 3-substituent were prepared by Friedel-Crafts reactions of a 3-hydroxymethyl-chlorin as one of the chlorophyll-a derivatives with benzo- and naphthohydroquinones, respectively, and successive oxidation of the 1,4-dihydroxy-aryl groups in the resulting dehydration products. The 3-quinonylmethyl-chlorins exhibited ultraviolet-visible absorption and circular dichroism spectra in acetonitrile, which were composed of those of the starting 3-hydroxymethyl-chlorin and the corresponding methylated benzo- and naphthoquinones. No intramolecular interaction between the chlorin and quinone π-systems was observed in the solution owing to the methylene spacer.
View Article and Find Full Text PDFJ Org Chem
January 2025
School of Chemistry, University of Hyderabad, C. R. Rao Road, Gachibowli, Hyderabad 500 046, India.
A facile two-step enantiospecific synthesis of 5,6,7,8-tetrahydroindolizine scaffolds has been developed via TMSOTf-promoted [3 + 2] cycloaddition between carbohydrate-derived spirocyclic donor-acceptor cyclopropanecarboxlates and alkyl/aryl nitriles followed by an intramolecular Mitsunobu reaction of the resulting chiral 2/5-(4-hydroxybutyl)pyrrole derivatives.
View Article and Find Full Text PDFAnal Chem
January 2025
Key Laboratory of Advanced Materials of Tropical Island Resources of Ministry of Education, School of Chemistry and Chemical Engineering, Hainan University, Haikou 570228, China.
As the third largest class of dyes in the world, triphenylmethane dyes are widely applied in colorimetric sensing. However, triphenylmethane dyes are commonly nonfluorescent, which limits their sensing applications. It is worthwhile to study the fluorescence off/on control of triphenylmethane dyes and promote the applications of triphenylmethane dyes in sensing technology.
View Article and Find Full Text PDFTetrahedron
February 2025
Department of Chemistry, Western Washington University, Bellingham, WA 98225 (USA).
Beta-hydroxy ketones can be reduced using a sequence of ruthenium-catalyzed silyl etherification followed by tetrabutylammonium fluoride (TBAF) promoted intramolecular hydrosilylation. Switching from TBAF to tetrabutylammonium difluorotriphenylsilicate (TBAT), even without first forming the silyl ether, gave cyclic dioxasilinane products. These somewhat sensitive compounds could be isolated pure by column chromatography using florisil as the stationary phase.
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