Variable-Temperature NMR Studies of Soluble Polymer-Supported Phosphine−Silver Complexes

2010 ◽  
Vol 75 (3) ◽  
pp. 873-878 ◽  
Author(s):  
David E. Bergbreiter ◽  
Yun-Chin Yang
Keyword(s):  
Variable Temperature ◽  
Silver Complexes ◽  
Nmr Studies ◽  
Soluble Polymer ◽  
Polymer Supported

Chiral "basket handle" binaphthyl porphyrins: synthesis, catalytic epoxidation and NMR conformational studies

2010 ◽  
Vol 14 (07) ◽  
pp. 646-659 ◽  
Author(s):  
Eric Rose ◽  
Emma Gallo ◽  
Nicolas Raoul ◽  
Léa Bouché ◽  
Ariane Pille ◽  
...  
Keyword(s):  
Time Scale ◽  
Room Temperature ◽  
Conformational Equilibrium ◽  
Variable Temperature ◽  
Conformational Exchange ◽  
Iron Catalysts ◽  
Nmr Studies ◽  
Conformational Studies ◽  
H Nmr ◽  
Catalytic Epoxidation

Three "basket handle" porphyrins have been prepared by condensation of tetrakis-(α,β,α,β-2-aminophenyl)porphyrin atropoisomer with 1,1′-binaphthyl, 2,2′-dimethoxy, -3,3′-dicarbonylchloride, -3,3′-diacetylchloride and -3,3′-dipropanoylchloride. The epoxidation of styrene with the three iron catalysts, obtained after metalation of the free porphyrins, occurs with good yields and moderate ee up to 54%. These porphyrins showed unexpected conformational differences, as revealed by NMR spectroscopy. In particular, variable temperature NMR studies showed that the methoxy group in one of them undergoes intermediate conformational exchange on the 1H NMR time scale at room temperature. Lowering the temperature to -50 °C revealed the presence of four states in slow exchange on the NMR time scale. These results evidence a dynamic conformational equilibrium of the binaphthyl handles that adopt different, asymmetric positions with respect to the porphyrin plane.

scholarly journals Variable temperature 1H NMR studies on Grubbs catalysts

2008 ◽  
Vol 693 (7) ◽  
pp. 1252-1260 ◽  
Author(s):  
Margaret M. Gallagher ◽  
A. Denise Rooney ◽  
John J. Rooney
Keyword(s):  
1H Nmr ◽  
Variable Temperature ◽  
Nmr Studies ◽  
Grubbs Catalysts

Soluble polymer-supported organocatalysts

2012 ◽  
Vol 85 (3) ◽  
pp. 493-509 ◽  
Author(s):  
Yun-Chin Yang ◽  
David E. Bergbreiter
Keyword(s):  
Transition Metal ◽  
Organic Synthesis ◽  
Metal Catalysts ◽  
Transition Metal Catalysts ◽  
Soluble Polymer ◽  
Soluble Polymers ◽  
The Past ◽  
Polymer Supports ◽  
Polymer Supported ◽  
Simple Product

Organocatalysts have been extensively studied for the past few decades as alternatives to transition-metal catalysts. Immobilizing organocatalysts on polymer supports allows easy recovery and simple product purification after a reaction. Select examples of recent reports that describe the potential advantages of using soluble polymers to prepare soluble polymer-supported organocatalysts useful in organic synthesis are reviewed.

Enantioselective Hydrolysis of Soluble Polymer-Supported Carboxylates

Synfacts ◽  
2010 ◽  
Vol 2010 (12) ◽  
pp. 1443-1443
Author(s):  
K. Matsumoto ◽  
M. Okudomi ◽  
K. Ageishi ◽  
T. Yamada ◽  
N. Chihara ◽  
...  
Keyword(s):  
Enantioselective Hydrolysis ◽  
Soluble Polymer ◽  
Polymer Supported ◽  
Hydrolysis Of

ChemInform Abstract: Highly Selective Intermolecular Heck Reaction for the Soluble Polymer Supported Synthesis of Glutamic Acid Analogues.

ChemInform ◽  
2010 ◽  
Vol 33 (12) ◽  
pp. no-no
Author(s):  
Berengere Sauvagnat ◽  
Frederic Lamaty ◽  
Rene Lazaro ◽  
Jean Martinez
Keyword(s):  
Glutamic Acid ◽  
Heck Reaction ◽  
Soluble Polymer ◽  
Polymer Supported
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