Gold-Catalyzed Synthesis of Furans and Furanones from Sulfur Ylides
作者:Xueliang Huang、Bo Peng、Marco Luparia、Luis F. R. Gomes、Luís F. Veiros、Nuno Maulide
DOI:10.1002/anie.201203637
日期:2012.8.27
A golden switch: Doubly stabilized sulfonium ylides can be coupled with alkynes in a gold‐catalyzed synthesis of heterocycles. This method hinges on a switch in the reactivity of the sulfur ylide resulting from the simple modification of the electron‐withdrawing moieties and leads to either furans or furanones bearing a quaternary center (see scheme).
A gold‐catalyzed asymmetriccyclopropanation of unactivated olefins with sulfoniumylides in the presence of a bimetallic catalyst with a novel dimeric TADDOL‐phosphoramidite ligand is reported. This transformation allows a rare gold‐catalyzed dynamic deracemization of chiral racemic substrates, where the same catalyst is responsible for several synergistic tasks in solution. The products are useful
Stereoselective intramolecular cyclopropanation through catalytic olefin activation
作者:Xueliang Huang、Sebastian Klimczyk、Luís F. Veiros、Nuno Maulide
DOI:10.1039/c2sc21914j
日期:——
A novel stereoselective and convergent catalytic method for the cyclopropanation of electron-neutral and -rich olefins by sulfonium ylides is reported which unusually proceeds through olefin activation rather than by metal carbene formation.