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Search for "Cinchona derivatives" in Full Text gives 4 result(s) in Beilstein Journal of Organic Chemistry.

Factors influencing the performance of organocatalysts immobilised on solid supports: A review

  • Zsuzsanna Fehér,
  • Dóra Richter,
  • Gyula Dargó and
  • József Kupai

Beilstein J. Org. Chem. 2024, 20, 2129–2142, doi:10.3762/bjoc.20.183

Graphical Abstract
  • influence of various linkers of cinchona squaramide organocatalysts immobilised on a poly(glycidyl methacrylate) (PGMA) solid support [127]. The support consisted of well-defined monodispersed PGMA microspheres, which were prepared through thorough parameter optimisation. Three amine-functionalised cinchona
  • derivatives 29–31 were immobilised on this polymer support by utilising its reactive epoxy groups (Scheme 9). These structurally diverse precatalysts were prepared by modifying the cinchona skeleton at different positions to investigate how the amino group-containing linker affects them. The immobilised
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Review
Published 26 Aug 2024

Recent advances in organocatalytic asymmetric aza-Michael reactions of amines and amides

  • Pratibha Sharma,
  • Raakhi Gupta and
  • Raj K. Bansal

Beilstein J. Org. Chem. 2021, 17, 2585–2610, doi:10.3762/bjoc.17.173

Graphical Abstract
  • -1,2,3-triazoles 35 in good yields (up to ≈72%) and excellent enantioselectivity (up to 99% ee) (Table 7) [41]. In an interesting study, Wu et al. screened a number of cinchona derivatives and squaramides for their relative catalytic efficacies for the enantioselective aza-Michael additions between
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Review
Published 18 Oct 2021

Controlling the stereochemistry in 2-oxo-aldehyde-derived Ugi adducts through the cinchona alkaloid-promoted electrophilic fluorination

  • Yuqing Wang,
  • Gaigai Wang,
  • Anatoly A. Peshkov,
  • Ruwei Yao,
  • Muhammad Hasan,
  • Manzoor Zaman,
  • Chao Liu,
  • Stepan Kashtanov,
  • Olga P. Pereshivko and
  • Vsevolod A. Peshkov

Beilstein J. Org. Chem. 2020, 16, 1963–1973, doi:10.3762/bjoc.16.163

Graphical Abstract
  • . Testing Ugi adduct 8h allowed us to highlight the possibility of simultaneous variation of acid, 2-oxo-aldehyde, and amine components. Overall, four cinchona derivatives were screened with 8h producing the fluorinated product 12h with moderate to good enantioselectivity, which was consistent with the
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Full Research Paper
Published 11 Aug 2020

Combined bead polymerization and Cinchona organocatalyst immobilization by thiol–ene addition

  • Kim A. Fredriksen,
  • Tor E. Kristensen and
  • Tore Hansen

Beilstein J. Org. Chem. 2012, 8, 1126–1133, doi:10.3762/bjoc.8.125

Graphical Abstract
  • water and copolymerized on heating by thiol–ene additions. The resultant spherical and gel-type polymer beads have been evaluated as organocatalysts in catalytic asymmetric transformations. Keywords: asymmetric catalysis; Cinchona derivatives; organocatalysis; polymerization; thiol–ene reaction
  • . Such polymer beads have provided good to excellent results as organocatalysts in various asymmetric transformations [6][7]. Cinchona derivatives are used in several types of organocatalysts, and they are all equipped with a pendant vinylic functionality susceptible to activation by chemical
  • transformations based on radical intermediates [1]. As a result, polymeric immobilization of Cinchona derivatives by using thiol–ene addition has a substantial history, founded on procedures developed already in the early 1970s [1]. Cinchona derivatives are either copolymerized with certain comonomers, such as
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Letter
Published 20 Jul 2012
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