Results 241 to 250 of about 216,387 (290)

ChemInform Abstract: Cycloadditions in Synthesis

ChemInform, 1997
AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
openaire   +4 more sources

Construction of Nine-Membered Heterocycles through Palladium-Catalyzed Formal [5+4] Cycloaddition.

Angewandte Chemie, 2017
The first catalytic formal [5+4] cycloaddition to prepare nine-membered heterocycles is presented. Under palladium catalysis, the reaction of N-tosyl azadienes and substituted vinylethylene carbonates (VECs) proceeds smoothly to produce benzofuran-fused ...
Li-Cheng Yang, Zi-Qiang Rong, Ya-Nong Wang, Zher Yin Tan, Min Wang, Yu Zhao   +5 more
semanticscholar   +1 more source

Recent Advances in the Catalytic Cycloaddition of 1,n-Dipoles

, 2018
Dipolar cycloaddition is one of the most valuable methods for synthesizing various carbo- and heterocycles because multiple carbon–carbon and carbon–heteroatom bonds form in a single step.
Nirupam De, E. Yoo
semanticscholar   +1 more source

Vinylethylene Carbonates as α,β-Unsaturated Aldehyde Surrogates for Regioselective [3 + 3] Cycloaddition.

Organic Letters, 2019
Herein, we report a novel stepwise addition-controlled ring size method, to access tetrahydropyrimidines through an operationally simple [3 + 3] cycloaddition of vinylethylene carbonates with triazinanes.
Yi Xu, Lu Chen, Yuwen Yang, Zhiqiang Zhang, Weibo Yang   +4 more
semanticscholar   +1 more source

Silver(I)- and Base-Mediated [3 + 3]-Cycloaddition of C,N-Cyclic Azomethine Imines with Aza-oxyallyl Cations.

Organic Letters, 2018
A silver(I) and base-mediated [3 + 3]-cycloaddition reaction of in situ generated C,N-cyclic azomethine imines with in situ formed aza-oxyallyl cations is reported.
Xiao Cheng, X. Cao, Jun Xuan, W. Xiao
semanticscholar   +1 more source

Dynamics of Carbene Cycloadditions

Journal of the American Chemical Society, 2011
Quasiclassical trajectory calculations using quantum mechanical energies and forces generated by the Venus and Gaussian programs provide for the first time a detailed dynamical picture of singlet carbene, CCl(2) and CF(2), cycloadditions to alkenes on the B3LYP/6-31G* surface.
K. N. Houk, Charles Doubleday, Lai Xu
openaire   +3 more sources

Iron-Catalyzed Radical Cycloaddition of 2H-Azirines and Enamides for the Synthesis of Pyrroles.

Organic Letters, 2018
A novel and efficient Fe-catalyzed radical cycloaddition of 2H-azirines and enamides for the synthesis of substituted pyrroles has been developed. The radical cycloaddition reaction proceeded through a conceptually new Fe(II)-catalyzed homolytic cleavage
Mi-Na Zhao, Zhihui Ren, Desuo Yang, Zheng‐Hui Guan   +3 more
semanticscholar   +1 more source

Bioconjugation by copper(I)-catalyzed azide-alkyne [3 + 2] cycloaddition.

Journal of the American Chemical Society, 2003
The copper-catalyzed cycloaddition reaction between azides and alkynes functions efficiently in aqueous solution in the presence of a tris(triazolyl)amine ligand. The process has been employed to make rapid and reliable covalent connections to micromolar
Qian Wang, T. Chan, Robert Hilgraf, V. Fokin, K. Sharpless, M. Finn   +5 more
semanticscholar   +1 more source

[2+2]Cycloaddition

1994
Die thermische [2+2]Cycloaddition von Alkenen 1 ist nach den Woodward-Hoffmann-Regeln 1) suprafacial symmetrieverboten und kann nur in speziellen Fallen erfolgreich durchgefuhrt werden. Hingegen ist das photochemische Pendant erlaubt und wird als praparativ wertvolle Methode zur Bildung von Vierringsystemen 2 vielfaltig genutzt.2–4)
Andreas Plagens, Thomas Laue
openaire   +2 more sources

Formal [5+3] Cycloaddition of Zwitterionic Allylpalladium Intermediates with Azomethine Imines for Construction of N,O‐Containing Eight‐Membered Heterocycles

, 2018
A formal [5+3] cycloaddition of zwitterionic allylpalladium intermediates with 1,3-dipoles is developed, providing N,O-containing eight-membered heterocyclic compounds in high yields.
Chunhao Yuan, Yang Wu, Dongqi Wang, Zhenhua Zhang, Chang Wang, Leijie Zhou, Cheng Zhang, B. Song, Hongchao Guo   +8 more
semanticscholar   +1 more source