Cobaltcomplex/Zn systems effectively catalyze the reductive coupling of activated alkenes with alkynes in the presence of water to give substituted alkenes with very high regio- and stereoselectivity in excellent yields. While the intermolecular reaction of acrylates, acrylonitriles, and vinyl sulfones with alkynes takes place in the presence of CoI2(PPh3)2/Zn, the reaction of enones and enals with
Direct β-Alkenylation of Ketones via Pd-Catalyzed Redox Cascade
作者:Chengpeng Wang、Alexander J. Rago、Guangbin Dong
DOI:10.1021/acs.orglett.9b01116
日期:2019.5.3
A direct β-alkenylation of simple ketones with alkenyl bromides is reported via a Pd-catalyzed redox cascade strategy. The reaction is redox neutral and directing-group-free, in the absence of strong acids or bases. Both cyclic and linear ketones are suitable substrates, and various alkenyl bromides can be coupled. The resulting β-alkenyl ketones are readily derivatized through diverse alkene functionalization
Catalytic Intermolecular Reductive Coupling of Enones and Alkynes
作者:Ananda Herath、Benjamin B. Thompson、John Montgomery
DOI:10.1021/ja073300q
日期:2007.7.1
A nickel-catalyzed intermolecular reductive coupling of enones and alkynes has been developed as a novel entry to gamma,delta-unsaturated ketones. The process does not require formation of a vinyl organometallic, and a variety of functional groups including free hydroxyls and esters are tolerated. A number of features that complement existing copper-mediated processes are highlighted.
Evolution of Efficient Strategies for Enone−Alkyne and Enal−Alkyne Reductive Couplings
作者:Wei Li、Ananda Herath、John Montgomery
DOI:10.1021/ja9083607
日期:2009.11.25
Strategies for the reductive coupling of enones or enals with alkynes have been developed. The reducing agents employed include organozincs, organoboranes, organosilanes, and methanol. The latter of these strategies is simple, cost-effective, and tolerant of many functional groups. Isotopic labeling strategies have provided supporting evidence for the mechanistic proposals.