Silver(I)-Catalyzed Cascade: Direct Access to Furans from Alkynyloxiranes
摘要:
Functionalized furans are conveniently formed by a new silver(I)-catalyzed reaction of alk-1-ynyl oxiranes in the presence of p-toluenesulfonic acid and methanol. Evidence supported a cascade mechanism.
On the Palladium(II)-Catalysed Oxidative Rearrangement of Propargylic Acetates
作者:A. Bartels、R. Mahrwald、K. Müller
DOI:10.1002/adsc.200303200
日期:2004.3
The catalytic transformation of propargylic acetates into the corresponding α-acetoxyenones in the presence of palladium(II) chloride is described. Water is a necessary component in this unusual oxidative rearrangement.
Dehydrative Cp*Co(III)-Catalyzed C–H Bond Allenylation
作者:Malay Sen、Pardeep Dahiya、J. Richard Premkumar、Basker Sundararaju
DOI:10.1021/acs.orglett.7b01415
日期:2017.7.21
unprecedented reactivity of Cp*Co(III) for the synthesis of tetrasubstituted allenes under mild conditions is disclosed. Electron-rich and highly nucleophilic cobalt facilitates the dehydrative C–H bond allenylation directly from propargylic alcohols without any derivatization. The reaction proceeds via reversible cyclometalation followed by alcohol-directed regioselective alkyne insertion and β-hydroxy elimination
Mechanistic Studies and Improvement of Coinage Metal-Catalyzed Transformation of Alkynyloxiranes to Furans: An Alcohol Addition−Cyclization−Elimination Cascade
作者:Aurélien Blanc、Katharina Tenbrink、Jean-Marc Weibel、Patrick Pale
DOI:10.1021/jo9008172
日期:2009.8.7
In the presence of alcohol Ag or Au salts or complexes catalyze the conversion of alkynyloxiranes to substituted furans. Both-catalysts are effective, and a large furan diversity can be obtained in high yield with one or the other catalyst. Mechanistic studies revealed that a cascade pathway and not the sometimes reported direct intra molecular nucleophilic addition of oxirane oxygen atom to intermediate acetylene-metal pi-complex occurs. Under the defined conditions, the intermediate formation of epoxide opening products has been identified. Depending on the catalyst, one or both of the latter cyclized to dihydrofurans, and further elimination of the alcohol led to the corresponding furans. These results highlight the duality between oxophilicity and alkynophilicity of Ag or Au salts.
Pb(OAc)4-Cu(OAc)2-mediated oxidation of 1-alkylcyclohexanols; ?-decomposition of 1-alkylcycloalkoxy radicals
作者:N. I. Kapustina、S. S. Spektor、G. I. Nikishin
DOI:10.1007/bf00960267
日期:1984.12
Untersuchungen über Synthesewege zu 2-Äthynyl-2-cyclopenten-1-onen