13159-19-8Relevant academic research and scientific papers
Highly functionalized and potent antiviral cyclopentane derivatives formed by a tandem process consisting of organometallic, transition-metal-catalyzed, and radical reaction steps
Jagtap, Pratap R.,Ford, Leigh,Deister, Elmar,Pohl, Radek,Cisarova, Ivana,Hodek, Jan,Weber, Jan,Mackman, Richard,Bahador, Gina,Jahn, Ullrich
supporting information, p. 10298 - 10304 (2014/08/18)
A simple modular tandem approach to multiply substituted cyclopentane derivatives is reported, which succeeds by joining organometallic addition, conjugate addition, radical cyclization, and oxygenation steps. The key steps enabling this tandem process are the thus far rarely used isomerization of allylic alkoxides to enolates and single-electron transfer to merge the organometallic step with the radical and oxygenation chemistry. This controlled lineup of multiple electronically contrasting reactive intermediates provides versatile access to highly functionalized cyclopentane derivatives from very simple and readily available commodity precursors. The antiviral activity of the synthesized compounds was screened and a number of compounds showed potent activity against hepatitisC and dengue viruses.
Palladium-Catalyzed highly diastereoselective oxidative cascade cyclization reactions
Yip, Kai-Tai,Zhu, Nian-Yong,Yang, Dan
supporting information; experimental part, p. 1911 - 1914 (2009/09/25)
Isoquinoline and quinoline have been discovered as novel ligands for palladium-catalyzed oxidative cascade cyclization reactions. With our new catalyst systems (Pd(OAc)2/isoquinoline or quinoline), unsaturated anilides cyclize under an oxygen atmosphere (1 atm) to furnish structurally versatile indoline derivatives in good yields. One C-N bond and two C-C bonds are formed in a single step with excellent diastereoselectivities (dr> 24:1).
Lithium malonate enolates as precursors for radical reactions - Convenient induction of radical cyclizations with either radical or cationic termination
Jahn, Ullrich,Hartmann, Philip,Dix, Ina,Jones, Peter G.
, p. 3333 - 3355 (2007/10/03)
Lithium malonate enolates 4 or 13 are oxidized to the corresponding radicals by ferrocenium hexafluorophosphate (1) or CuCl2 (2). Trapping by TEMPO (5) to produce 6, dimerization to 7, or radical 5-exo cyclizations are possible subsequent reaction steps following radical generation. The structure of the radical cyclization acceptor determines the outcome of the overall reaction sequence. Tertiary benzylic, alkyl, and α-alkoxy radicals are oxidized by 1. The carbenium ions are stabilized by nucleophilic trapping or deprotonation to give compounds 14 and 18. Secondary alkyl and vinyl radicals are not oxidized and, in the absence of trapping reagents, form radical-derived products. Radical 5-exo cyclization of 13 induced by CuCl2 (2) was also efficient. At least for alkyl radicals, however, ligand transfer is the exclusive stabilization pathway, giving access to chloroalkylcyclopentane derivatives 21. Radical scavenging studies revealed that malonyl radical trapping is slow, so that 5-exo cyclizations occurred. The cyclized radicals couple with TEMPO (5) to afford oxygenated cyclopentane derivatives 31, depending on the rate of radical SET oxidation. The reaction behavior of compounds 14, 22, 23, and 31 was investigated. Mechanistic issues are discussed and implications for synthetic planning are given.
