[reaction: see text] 2-Polyfluoroalkylchromones react with 1,3,3-trimethyl-3,4-dihydroisoquinolines to give zwitterionic axially chiral 6,7-dihydrobenzo[a]quinolizinium derivatives in high yields. In addition, performing this reaction with aromatic methylketimines is a simple and convenient synthesis of 2,6-diaryl-4-polyfluoroalkylpyridines.
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http://dx.doi.org/10.1021/ol0351448 | DOI Listing |
Org Lett
September 2023
Department of Chemistry, China Agricultural University, Beijing 100193, P. R. China.
The 5-allenyloxazolidine-2,4-diones had been synthesized as novel precursors of π-allyl palladium zwitterion and were applied in a palladium-catalyzed enantioselective (3 + 2) annulation by using barbiturate-derived alkenes as the reaction partner in the presence of an axially chiral phosphoramidite ligand. This reaction proceeded smoothly under mild reaction conditions, affording highly functionalized spirobarbiturate-γ-lactam derivatives in excellent yields along with high diastereo- and enantioselectivities. The scale-up reaction and further transformation of the product were also successful.
View Article and Find Full Text PDFDalton Trans
June 2023
Department of Chemistry, University of Patras, 26504 Patras, Greece.
The initial use of a tetradentate Schiff base (LH) derived from the 2 : 1 condensation between 2-hydroxyacetophenone and cyclohexane-1,2-diamine in 4f-metal chemistry is described. The 1 : 2 reaction of Ln(NO)·HO (Ln = lanthanoid or yttrium) and LH in MeOH/CHCl has provided access to isostructural complexes [Ln(NO)(L'H)(MeOH)] in moderate to good yields. Surprisingly, the products contain the corresponding Schiff base ligand L'H possessing six aliphatic -CH- groups instead of the -CH-(CH)-CH- unit of the cyclohexane ring, an unusual ring-opening of the latter has occurred.
View Article and Find Full Text PDFJ Phys Chem A
April 2023
Department of Chemistry and Centre for Energy Science, Indian Institute of Science Education and Research, Pune, Dr. Homi Bhabha Road, Pashan, Pune, 411008 Maharashtra, India.
In this work, the possible mechanisms for the reactions of CO with various positional isomers of methylpiperidines (MPs) (N-MP, 2-MP, 3-MP, and 4-MP) including the effect of aqueous solvation have been explored using quantum chemical methods. The major pathways investigated for CO capture in aqueous amines are carbamate formation, its hydrolysis, and the bicarbonate formation (CO + HO + MP) reaction. The calculations indicate that an axial orientation for the methyl group and an equatorial for the COO group could be energetically ideal in the carbamate product of MPs.
View Article and Find Full Text PDFOrg Biomol Chem
January 2023
Institute of Research and Development, Duy Tan University, Da Nang 550000, Vietnam.
Asymmetric organocatalysis is a growing method for the synthesis of axially chiral tetrasubstituted allenes, the most challenging one among allene syntheses. In this method, chiral organocatalysts such as phase-transfer catalysts, peptides, disulfonimides, and binaphthyl/bispiro phosphoric acids have displayed remote control of regio- and stereoselectivity. Highly functionalized enantiopure allenes including those with an adjacent tertiary or quaternary stereocenter have been efficiently prepared with high levels of regio-, diastereo-, and enantioselectivity using this method.
View Article and Find Full Text PDFACS Omega
October 2022
Research Center of Henan Provincial Agricultural Biomass Resource Engineering and Technology, College of Life Science and Agricultural Engineering, Nanyang Normal University, Nanyang 473061, Henan, China.
The mass-transfer process of l-tryptophan (l-Trp) in the hydrophobic interaction/ion-exchange mixed-mode resin HD-1 particles and fixed bed was studied experimentally and theoretically. The adsorption kinetics of l-Trp in single-component and multicomponent adsorption systems was investigated under different pH conditions. The co-adsorption of sodium ions (Na) and l-Trp anions was found to be negligible.
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