Results 21 to 30 of about 73,410 (278)

Synthesis of pyrrolizines by intramolecular capture of 1,4-dipolar intermediates in reactions of enamines with dimethyl acetylenedicarboxylate [PDF]

open access: yes, 1981
Solvent polarity and reaction temperature strongly influence the reactions of dimethyl acetylenedicar-boxylate (DMAD) with 1-pyrrolidinyl enamines of acyclic and cyclic ketones. Whereas DMAD and 1-[1-phenyl-2-(phenylthio)ethenyl]pyrrolidine (3) give only
Harkema, S.   +5 more
core   +3 more sources

Efficient fabrication of oxazolidinones for the carboxylative cyclization with carbon dioxide

open access: yesJournal of CO2 Utilization, 2023
Overuse of fossil energy has accelerated the development of industrialization and improved the quality of human life. However, it also leads to the excessive emission of CO2, and the greenhouse effect is threatening global climate stability and human ...
Xin Yang   +5 more
doaj   +1 more source

Photochemical Approaches to Complex Chemotypes: Applications in Natural Product Synthesis. [PDF]

open access: yes, 2016
The use of photochemical transformations is a powerful strategy that allows for the formation of a high degree of molecular complexity from relatively simple building blocks in a single step. A central feature of all light-promoted transformations is the
Kärkäs, Markus D.   +2 more
core   +2 more sources

Highly Efficient Construction of Sugar-Fused Spirochromanono Pyrrolidines/Pyrrolizidines/Thiolizidines via 1,3-Dipolar Cycloaddition of Azomethine Ylides

open access: yesSynOpen, 2017
A variety of sugar-fused chromanono pyrrolidines/pyrrolizidines/thiolizidines have been synthesized by intermolecular 1,3-dipolar cycloaddition reaction of azomethine ylides (generated from glucose aldehyde and different secondary amino acids) with ...
Sirisha Nallamala   +2 more
doaj   +1 more source

Halogenation effects in Intramolecular Furan Diels-Alder reactions:broad scope synthetic and computational studies [PDF]

open access: yes, 2013
For the first time a comprehensive synthetic and computational study of the effect of halogen substitution on both furan and dienophile for the intramolecular Furan Diels-Alder (IMDAF) reaction has been undertaken.
Bebbington, Magnus William Paul   +3 more
core   +1 more source

Ab initio study of the mechanism of formation of a spiro-Sn-heterocyclic ring compound by the cycloaddition reaction of H2C=Sn: and ethylene [PDF]

open access: yesJournal of the Serbian Chemical Society, 2019
X2C=Sn: (X = H, Me, F, Cl, Br, Ph, Ar…) are new species of chemistry. The cycloaddition reactions of X2C=Sn: is a new study field of stannylene chemistry.
Tan Xiaojun, Lu Xiuhui
doaj   +1 more source

Stereodivergent, Diels-Alder-initiated organocascades employing α,β-unsaturated acylammonium salts: scope, mechanism, and application. [PDF]

open access: yes, 2017
Chiral α,β-unsaturated acylammonium salts are novel dienophiles enabling enantioselective Diels-Alder-lactonization (DAL) organocascades leading to cis- and trans-fused, bicyclic γ- and δ-lactones from readily prepared dienes, commodity acid chlorides ...
Abbasov, Mikail E   +3 more
core   +2 more sources

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  

Phosphoramidite Gold(I)-Catalyzed Diastereo- and Enantioselective Synthesis of 3,4-Substituted Pyrrolidines [PDF]

open access: yes, 2011
In this article the utility of phosphoramidite ligands in enantioselective AuI catalysis was explored in the development of highly diastereo- and enantioselective AuI-catalyzed cycloadditions of allenenes.
Benitez, Diego   +4 more
core   +3 more sources

Coordinatively unsaturated ruthenium complexes as efficient alkyne-azide cycloaddition catalysts [PDF]

open access: yes, 2012
The performance of 16-electron ruthenium complexes with the general formula Cp*Ru(L)X (in which L = phosphine or N-heterocyclic carbene ligand; X = Cl or OCH2CF3) was explored in azide−alkyne cycloaddition reactions that afford the 1,2,3- triazole ...
Broggi, Julie   +6 more
core   +2 more sources

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