A gold-catalyzed hydrogen bond-directed tandem cyclization strategy to synthesize indeno-chromen-4-one and indeno-quinolin-4-one derivatives has been developed. The hydrogen bond existing between the hydroxyl group (or the amide group) and the carbonyl group played an essential role in controlling the selectivity, which was confirmed by both experimental and theoretical evidence.
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http://dx.doi.org/10.1039/c6cc05391b | DOI Listing |
Angew Chem Int Ed Engl
June 2024
Institute of Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Baldiri Reixac 10, Barcelona, E-08028, Spain.
A combined computational and experimental approach allowed us to develop overall the most selective catalyst for the direct hydrogenation of N-methyl, N-alkyl and N-aryl imines described to date. Iridium catalysts with a cyclometallated cyclic imide group provide selectivity of up to 99 % enantiomeric excess. Computational studies show that the selectivity results from the combined effect of H-bonding of the imide C=O with the substrate iminium ion and a stabilizing π-π interaction with the cyclometallated ligand.
View Article and Find Full Text PDFChemistry
February 2024
Graduate School of Advanced Science and Engineering, Hiroshima University, Higashi-Hiroshima, 739-8526, Japan.
The cycloaddition of nitrile oxides with ethynyl-B(dan) (dan=naphthalene-1,8-diaminato) allowed the facile preparation of diverse isoxazolyl-B(dan) compounds, all of which displayed excellent protodeborylation-resistant properties. The dan-installation on the boron center proves vital to the high stability of the products as well as the perfect regioselectivity arising from hydrogen bond-directed orientation in the cycloaddition. The diminished boron-Lewis acidity of ethynyl-B(dan) also renders it amenable to azide-alkyne cycloaddition, Larock indole synthesis and related heteroannulations.
View Article and Find Full Text PDFJ Phys Chem A
December 2023
Department of Chemistry, University of Minnesota, 207 Pleasant Street, SE, Minneapolis, Minnesota 55455, United States.
The 1:1 complex formed from trifluoroacetic acid (TFA) and trimethylamine (TMA) has been observed in the gas phase by rotational spectroscopy and further investigated by DFT and MP2 methods. Spectra of both the parent form and the -OD isotopologue have been obtained. The complex is structurally similar to a hydrogen bonded system, with the O-H bond directed toward the nitrogen of the TMA.
View Article and Find Full Text PDFOrg Biomol Chem
May 2023
Department of Chemistry, Kazi Nazrul University, Asansol, West Bengal 713340, India.
High-fidelity optical detection of picric acid (PA) is necessary due to its toxic and explosive nature. Moreover, PA is a molecule with versatile features, such as hydrogen bond or proton donor-acceptor centers, extremely low p, highly electron-deficient center, high water solubility, . These unique features and concerns stimulated us to write this review article on the small-molecule-based optical detection of PA.
View Article and Find Full Text PDFChemistry
October 2022
Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an, 710119, P. R. China.
Elaborately designed π-stacked molecular aggregates are significant for modulation of photophysical properties of polycyclic aromatic hydrocarbons (PAHs). Herein, a double hydrogen-bonds trussed di(pyridyl)pyrrole-perylene bisimide (HDPP-PBI) was designed and its dimerization behavior was studied. HDPP-PBI tends to form a quadruple PBI stack with a dimerization constant of ∼5.
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