Rhodium‐NHC‐Catalyzed
gem
‐Specific
O
‐Selective Hydropyridonation of Terminal Alkynes
摘要:
AbstractThe dinuclear complex [Rh(μ‐Cl)(η2‐coe)(IPr)]2 is an efficient catalyst for the O‐selective Markovnikov‐type addition of 2‐pyridones to terminal alkynes. DFT calculations support a hydride‐free pathway entailing intramolecular oxidative protonation of a π‐alkyne by a κ1N‐hydroxypyridine ligand. Subsequent O‐nucleophilic attack on a metallacyclopropene species affords an O‐alkenyl‐2‐oxypyridine chelate rhodium intermediate as the catalyst resting state. The release of the alkenyl ether is calculated as the rate‐determining step.
Synthesis of 1-(1-Arylvinyl)pyridin-2(1<i>H</i>)-ones from Ketones and 2-Fluoropyridine
作者:Takuji Kawamoto、Shunya Ikeda、Akio Kamimura
DOI:10.1021/acs.joc.1c01615
日期:2021.10.1
for the synthesis of N-vinyl-substituted pyridones from ketones and 2-fluoropyridine in the presence of trifluoromethane sulfonic anhydride, followed by a base treatment. Various ketones with electron-donating or electron-withdrawing groups at the benzene rings can be used in this reaction. A preliminary mechanistic study indicates that it is not very likely that both vinyl triflates and vinyl cations
Rhodium‐NHC‐Catalyzed
<i>gem</i>
‐Specific
<i>O</i>
‐Selective Hydropyridonation of Terminal Alkynes
作者:María Galiana‐Cameo、Raúl Romeo、Asier Urriolabeitia、Vincenzo Passarelli、Jesús J. Pérez‐Torrente、Victor Polo、Ricardo Castarlenas
DOI:10.1002/anie.202117006
日期:2022.5.9
AbstractThe dinuclear complex [Rh(μ‐Cl)(η2‐coe)(IPr)]2 is an efficient catalyst for the O‐selective Markovnikov‐type addition of 2‐pyridones to terminal alkynes. DFT calculations support a hydride‐free pathway entailing intramolecular oxidative protonation of a π‐alkyne by a κ1N‐hydroxypyridine ligand. Subsequent O‐nucleophilic attack on a metallacyclopropene species affords an O‐alkenyl‐2‐oxypyridine chelate rhodium intermediate as the catalyst resting state. The release of the alkenyl ether is calculated as the rate‐determining step.