A practical and additive-free method for the prenylation of chalcones using prenylzinc is reported. The protocol described is attractive because it provides access to a new class of prenylated chalcone derivatives derived from two classes of natural products in a simple, high-yielding and regioselective synthetic step. Furthermore, the application of other allylic reagents in our new protocol is demonstrated. A plausible mechanism that invokes steric factors to account for the α-regioselective outcome is proposed.
The Buchwald–Hartwig coupling/Michael addition sequence has been successfully applied to the synthesis of functionalized 1,2-disubstituted 4-quinolones using Pd(OAc)2 as a catalyst and PPh3 as a ligand. Under these conditions, the intermediate products first formed from chalcones and primaryamines underwent catalytic dehydrogenation to yield the 1,2-disubstituted 4-quinolones.
Cu-Catalyzed one-pot synthesis of thiochromeno-quinolinone and thiochromeno-thioflavone <i>via</i> oxidative double hetero Michael addition using <i>in situ</i> generated nucleophiles
作者:Nallappan Sundaravelu、Govindasamy Sekar
DOI:10.1039/d0cc03210g
日期:——
catalyzed three-component synthesis of π-conjugated tetracyclic thiochromeno-quinolinone and thiochromeno-thioflavone was established via oxidative double hetero Michael additionusing in situ generated nucleophiles. Xanthate plays a dual role as an odourless sulfur source and a chemoselective reducing agent. The in situ formed iodine plays a crucial role in the oxidation step.
Copper(0)/Selectfluor System-Promoted Oxidative Carbon–Carbon Bond Cleavage/Annulation of <i>o</i>-Aryl Chalcones: An Unexpected Synthesis of 9,10-Phenanthraquinone Derivatives
作者:Hanyang Bao、Zheng Xu、Degui Wu、Haifeng Zhang、Hongwei Jin、Yunkui Liu
DOI:10.1021/acs.joc.6b02212
日期:2017.1.6
A general and efficient protocol for the synthesis of 9,10-phenanthraquinone derivatives has been successfully developed involving a copper(0)/Selectfluor system-promoted oxidative carbon–carbonbond cleavage/annulation of o-aryl chalcones. A variety of substituted 9,10-phenanthraquinones were synthesized in moderate to good yields under mild reaction conditions.
utilised as a non-covalent Brønsted base catalyst in the 1,6-conjugate addition of carbon nucleophiles to p-QMs. This protocol makes it possible to access unsymmetrical diaryl- and triarylmethanes in good to excellent yields. Further, this catalyst was also explored in the 1,4-conjugate addition of carbon nucleophiles to enone systems.