Results 51 to 60 of about 27,886 (261)

Asymmetric 1,3-Dipolar Cycloadditons of Stabilized Azomethine Ylides with Nitroalkenes [PDF]

open access: yes, 2014
This review highlights the biological importance of many polysubstituted nitro-prolines and -pyrrolidines. Their preparation using asymmetric 1,3-dipolar cycloadditions of azomethine ylides with nitroalkenes using diastereoselective and enantioselective ...
Nájera, Carmen, Sansano, Jose M.
core   +2 more sources

A Convenient Synthesis of Novel Isoxazolidine and Isoxazole Isoquinolinones Fused Hybrids

open access: yesMolecules, 2023
Isoxazolidine, isoxazole, and isoquinolinone rings are present in the structure of several natural products and/or pharmaceutically interesting compounds.
Konstantinos A. Ouzounthanasis   +2 more
doaj   +1 more source

Nucleophilicity and Electrophilicity Parameters for Predicting Absolute Rate Constants of Highly Asynchronous 1,3-Dipolar Cycloadditions of Aryldiazomethanes.

open access: yesJournal of the American Chemical Society, 2018
Kinetics of the reactions of aryldiazomethanes (ArCHN2) with benzhydrylium ions (Ar2CH+) have been measured photometrically in dichloromethane.
Harish Jangra   +7 more
semanticscholar   +1 more source

Concerted [4 + 2] and Stepwise (2 + 2) Cycloadditions of Tetrafluoroethylene with Butadiene: DFT and DLPNO-UCCSD(T) Explorations. [PDF]

open access: yes, 2020
Tetrafluoroethylene and butadiene form the 2 + 2 cycloadduct under kinetic control, but the Diels-Alder cycloadduct is formed under thermodynamic control. Borden and Getty showed that the preference for 2 + 2 cycloaddition is due to the necessity for syn-
Houk, KN   +4 more
core  

Recent advances in the catalytic asymmetric 1,3-dipolar cycloaddition of azomethine ylides [PDF]

open access: yes, 2014
Catalytic asymmetric 1,3-dipolar cycloadditions of azomethine ylides have turned out to be one of the most efficient methods for the preparation of enantioenriched pyrrolidines.
Adrio, Javier, Carretero, Juan C.
core   +2 more sources

The [4+2]‐Cycloaddition of α‐Nitrosoalkenes with Thiochalcones as a Prototype of Periselective Hetero‐Diels–Alder Reactions—Experimental and Computational Studies [PDF]

open access: yes, 2020
The [4+2]‐cycloadditions of α‐nitrosoalkenes with thiochalcones occur with high selectivity at the thioketone moiety of the dienophile providing styryl‐substituted 4H‐1,5,2‐oxathiazines in moderate to good yields.
Boger D. L.   +8 more
core   +1 more source

Additive-assisted regioselective 1,3-dipolar cycloaddition of azomethine ylides with benzylideneacetone

open access: yesBeilstein Journal of Organic Chemistry, 2014
1,3-Dipolar cycloadditions of isatins, benzylamine and benzylideneacetones were studied to prepare a series of novel spiropyrrolidine-oxindoles – 4′-acetyl-3′,5′-diarylspiro[indoline-3,2′-pyrrolidin]-2-ones and 3′-acetyl-4′,5′-diarylspiro[indoline-3,2 ...
Chuqin Peng   +5 more
doaj   +1 more source

[4 + 2] Cycloadditions of diphenylketene with a highly substituted 1,3-diene [PDF]

open access: yes, 1987
Diphenylketene (2) undergoes [4 + 2] cycloadditions with the s-cis fixed diene (1) to give the dihydropyran (3) and the cyclohexenone (4)
Heigl, Ulrich W., Mayr, Herbert
core   +1 more source

Advancing from MOFs and COFs to Functional Macroscopic Porous Constructs

open access: yesAdvanced Materials, EarlyView.
This review study investigates the recent progress and methodologies for manufacturing metal–organic framework (MOF) or covalent–organic framework (COF)‐based 3D structured macroscopic porous constructs with high structural integrity, providing the possibility to control their porosity across dimensions.
Seyyed Alireza Hashemi   +8 more
wiley   +1 more source

1,3-Dipolar cycloadditions of fluorinated nitrones with thioketones [PDF]

open access: yesJournal of Fluorine Chemistry, 2014
AbstractReadily available fluorinated nitrones (IV) and (XIV) are used in 1,3‐dipolar cycloadditions with thioketones affording 1,4,2 oxathiazolidines in a regioselective manner.
Mlostoń, Grzegorz   +5 more
openaire   +3 more sources

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