Ir-catalyzed [3 + 2] annulation of cyclic N-sulfonyl ketimines with 1,3-dienes, in which an aryliridium intermediate is formed via C-H activation, gives aminoindane derivatives in high yields with high regio- and diastereoselectivity.
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http://dx.doi.org/10.1021/ja311968d | DOI Listing |
Angew Chem Int Ed Engl
December 2024
University of Copenhagen, Department of Chemistry, Universitetsparken 5, DK-2100, Copenhagen, DENMARK.
The introduction of 4,5-dihydroazuleno[2,1,8-ija]azulene as a central core between two 1,4-dithiafulvene (DTF) units provides a novel class of extended tetrathiafulvalene (TTF) electron donors. Herein we present the synthesis of such compounds with the azulenoazulene further expanded by annulation to benzene, naphthalene, or thiophene rings. Moreover, unsymmetrical donor-acceptor chromophores with one DTF and one carbonyl at the central core are presented.
View Article and Find Full Text PDFOrg Lett
December 2024
Department of Chemistry, Indian Institute of Technology Ropar, Rupnagar, Punjab 140001, India.
Developing asymmetric transformations using electroredox and N-heterocyclic carbene (NHC)-catalyzed radical pathways is still desirable and challenging. Herein, we report an iodide-promoted β-carbon activation (LUMO-lowering process) of enals via electroredox carbene catalysis coupled with a hydrogen evolution reaction (HER). This strategy offers an environmentally friendly and sustainable route for rapidly assembling synthetically useful chiral naphthopyran-3-one in good to excellent yield and enantioselectivity using traceless electrons as inexpensive and greener oxidants.
View Article and Find Full Text PDFJ Org Chem
December 2024
Henan Key Laboratory of Natural Medicine Innovation and Transformation, State Key Laboratory of Antiviral Drugs, Henan University, Kaifeng, Henan 475004, P. R. China.
A highly stereoselective protocol for the (3 + 2)-annulation of biphenyl-bridged seven-membered cyclic -sulfonylimines with γ-hydroxy-α,β-unsaturated ketones was developed. The reactions afforded a wide range of chiral [5.7]-fused ε-sultams bearing N-adjacent 1,3-stereocenters in excellent yields (93-98% yields) and high enantio/diastereoselectivities (up to >99% ee, >20:1 d.
View Article and Find Full Text PDFChem Sci
November 2024
Frontier Institute of Science and Technology (FIST), Xi'an Jiaotong University Yanxiang Road 99 Xi'an 710045 China
The first Ni-catalyzed asymmetric decarboxylative strategy for the construction of carbocycles with contiguous quaternary all-carbon stereocenters is reported. The key to the success of these reactions is the utilization of rationally designed allenylic methylene cyclic carbonates as substrates with Ni catalysis. The floppy allenylic group exerts unique electronic properties on the carbonate, which allows further asymmetric nucleophilic annulations with alkenes.
View Article and Find Full Text PDFJ Org Chem
December 2024
State Key Laboratory of Chemical Oncogenomics, Shenzhen Graduate School of Peking University, Shenzhen 518055, China.
We have developed a hemin-catalyzed biomimetic oxidative annulation of 2,3-dihydroxybenzoic acid with an array of cyclic enamines to form isochromanones in good to excellent yields and high regioselectivity. This formal [4+2] cycloaddition protocol showed high efficiency and remarkable functional group tolerance. Mechanistic studies indicate the involvement of a single-electron oxidation pathway.
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