Ph3PAuNTf2 as a Superior Catalyst for the Selective Synthesis of 2H-Chromenes: Application to the Concise Synthesis of Benzopyran Natural Products
作者:Ioannis N. Lykakis、Christina Efe、Charis Gryparis、Manolis Stratakis
DOI:10.1002/ejoc.201001674
日期:2011.4
Ph3PAuNTf2 (≈1 mol-%) catalyzes the selective cycloisomerization of substituted aryl propargylethers into 2H-chromenes in excellent yields. Benzofuran byproducts are formed only in the case of electron-deficient arenes, in up to 7 % relative yield. The Ph3PAuNTf2-catalyzed cyclization of aryl propargylethers was applied as a key step to the concise synthesis of the naturally occurring benzopyrans
Indium-catalyzed intramolecular hydroarylation of aryl propargyl ethers
作者:Lorena Alonso-Marañón、M. Montserrat Martínez、Luis A. Sarandeses、José Pérez Sestelo
DOI:10.1039/c4ob02033b
日期:——
Indium(III) halides catalyze efficiently the intramolecularhydroarylation (IMHA) of aryl propargyl ethers. The reaction proceeds regioselectively with terminal and internal alkynes bearing electron-rich and electron-deficient substituents in the benzenes and alkynes affording only the 6-endo dig cyclization product. Additionally, a sequential indium-catalyzed IMHA and palladium-catalyzed Sonogashira
Gold nanoparticles supported on TiO<sub>2</sub>catalyse the cycloisomerisation/oxidative dimerisation of aryl propargyl ethers
作者:Christina Efe、Ioannis N. Lykakis、Manolis Stratakis
DOI:10.1039/c0cc03353g
日期:——
Gold nanoparticles supported on TiO2 (∼1%) catalyse in high yields the selective cycloisomerisation of aryl propargyl ethers into the corresponding 2H-chromenes, under heterogeneous conditions. 2H,2′H-3,3′-Bichromenes resulting from a catalytic oxidative dimerization pathway are also formed as by-products.
Mild and Selective Hydrogenation of Unsaturated Compounds Using Mn/Water as a Hydrogen Gas Source
作者:Jennifer Rosales、Tania Jiménez、Rachid Chahboun、Miguel A. Huertos、Alba Millán、José Justicia
DOI:10.1021/acs.orglett.3c03664
日期:2024.3.22
A mild and highly selective reduction of alkenes and alkynes using Mn/water is described. The highly controlled generation of H2 allows the selective reduction of these compounds in the presence of labile functional groups under mild and environmentally acceptable conditions.