Domino Meyer-Schuster/Arylation Reaction of Alkynols or Alkynyl Hydroperoxides with Diazonium Salts Promoted by Visible Light under Dual Gold and Ruthenium Catalysis
作者:Benito Alcaide、Pedro Almendros、Eduardo Busto、Amparo Luna
DOI:10.1002/adsc.201600158
日期:2016.4.28
alkynyl hydroperoxides using equimolar amounts of diazoniumsalts at room temperature has been achieved through application of a gold/photoredox dual catalytic system. The excess of external reagents (oxidant or base) and high temperatures required by previous arylative Meyer–Schuster rearrangement protocols are avoided by exploitation of a visiblelight‐mediated process.
Multicomponent Domino Approaches for the Synthesis of Spirooxazolidine‐2‐thiones and Spirooxothiolane‐2‐imines
作者:Divakar Reddy Indukuri、Gal Reddy Potuganti、Arsha Maria Cherian、Jagadeesh Babu Nanubolu、Yarasi Soujanya、Manjula Alla
DOI:10.1002/ejoc.202100739
日期:2021.10.14
and spirooxothiolane-2-imines starting from isatin, phenyl acetylene and isothiocyanates has been accomplished. The reactivity of ambident nucleophilic sites: nitrogen and sulfur in an isothiocyanate is explored and an attempt has been made to fine tune the reactionparameters for product selectivity. The domino reaction proceeds by the addition and 5-exo dig cyclization via hydroamination/hydrothiolation
Transition-Metal-Free Cyclization of Propargylic Alcohols with Aryne: Synthesis of 3-Benzofuranyl-2-oxindole and 3-Spirooxindole Benzofuran Derivatives
propargylic alcohols with aryne is reported, providing a novel method for the synthesis of 3-benzofuranyl-2-oxindole and 3-spirooxindole benzofuran scaffolds via a propargyl Claisen rearrangement/cycloaddition pathway. The nature of the substituent on acetylene group of propargylic alcohol influences the outcome of the reaction. The protocol offers a transition-metal-free and operationally simple methodology
Light-Stable Silver N-Heterocyclic Carbene Catalysts for the Alkynylation of Ketones in Air
作者:Faïma Lazreg、Mathieu Lesieur、Andrew J. Samson、Catherine S. J. Cazin
DOI:10.1002/cctc.201500869
日期:2016.1
N‐Heterocyclic carbene (NHC) silver(I) complexes were employed efficiently in the alkynylation of ketones. These cationic complexes were highly active and efficient under mild conditions and in air without the need for an additive. The mechanism of this transformation was investigated. Experiments suggest that the formation of a silver acetylide key intermediate and the release of one ligand from the
Synthesis of 3-ethynyl-3-hydroxy-2-oxindoles and 3-hydroxy-3-(indol-3-yl) indolin-2-ones using CuWO4 nanoparticles as recyclable heterogeneous catalyst in aqueous medium
acetylenes (spC-H activation) and selective synthesis of 3-hydroxy-3-(indol-3-yl) indolin-2-ones and 3,3′-bis(indolyl)indolin-2-ones (via Friedel-Crafts alkylation reaction) is reported in presence of CuWO4 (10 mol%) nanoparticles in aqueous medium. The catalyst was regenerated and reused up to 6 cycles without losing catalytic activity. This is the first report for the spC-H activation using CuWO4