Models for oxygenases that catalyze the cleavage of carbon-carbon bonds: kinetics and mechanism of the decomposition of 2,3-dimethyl-3-peroxyindolenines in aqueous solution

1982 ◽  
Vol 104 (15) ◽  
pp. 4203-4211 ◽  
Author(s):  
Mark S. Fraser ◽  
Gordon A. Hamilton
Keyword(s):  
Aqueous Solution ◽  
Kinetics And Mechanism ◽  
Carbon Carbon Bonds ◽  
Carbon Bonds

Complexes of carbohydrates with metal cations. III. Conformations of alditols in aqueous solution

1974 ◽  
Vol 27 (7) ◽  
pp. 1447 ◽  
Author(s):  
SJ Angyal ◽  
D Greeves ◽  
JA Mills
Keyword(s):  
Aqueous Solution ◽  
Complex Formation ◽  
Metal Ions ◽  
Chloroform Solution ◽  
Metal Cations ◽  
Carbon Carbon Bonds ◽  
Carbon Bonds ◽  
Oxygen Atoms

Complex formation of alditols with metal ions in aqueous solution has been investigated by electrophoresis and by the study of the N.M.R. spectra in the presence of europium ions. Complexing occurs at three consecutive oxygen atoms which are in a gauche-gauche arrangement; the energy required to form this arrangement (by rotation around carbon-carbon bonds) determines the extent of complex formation. It appears that the alditols in aqueous solution are essentially in the same conformations as are their acetates in chloroform solution.

Kinetics and mechanism of the reaction of iron(III) with 6-methyl-2,4-heptanedione and 3,5-heptanedione

1990 ◽  
Vol 55 (8) ◽  
pp. 1984-1990 ◽  
Author(s):  
José M. Hernando ◽  
Olimpio Montero ◽  
Carlos Blanco
Keyword(s):  
Aqueous Solution ◽  
Metal Ion ◽  
Activation Parameters ◽  
Enol Form ◽  
Kinetics And Mechanism ◽  
Kinetic Constants ◽  
Steric Factors ◽  
Kinetics Of ◽  
Mechanism Of The Reaction

The kinetics of the reactions of iron(III) with 6-methyl-2,4-heptanedione and 3,5-heptanedione to form the corresponding monocomplexes have been studied spectrophotometrically in the range 5 °C to 16 °C at I 25 mol l-1 in aqueous solution. In the proposed mechanism for the two complexes, the enol form reacts with the metal ion by parallel acid-independent and inverse-acid paths. The kinetic constants for both pathways have been calculated at five temperatures. Activation parameters have also been calculated. The results are consistent with an associative activation for Fe(H2O)63+ and dissociative activation for Fe(H2O)5(OH)2+. The differences in the results for the complexes of heptanediones studied are interpreted in terms of steric factors.

scholarly journals Broad scope gold(i)-catalysed polyenyne cyclisations for the formation of up to four carbon–carbon bonds

2017 ◽  
Vol 15 (10) ◽  
pp. 2163-2167 ◽  
Author(s):  
Zhouting Rong ◽  
Antonio M. Echavarren
Keyword(s):  
Single Step ◽  
Simultaneous Formation ◽  
Broad Scope ◽  
Carbon Carbon Bonds ◽  
Carbon Bonds ◽  
First Time ◽  
High Stereoselectivity

The polycyclisation of polyeneynes catalyzed by gold(i) has been extended for the first time to the simultaneous formation of up to four carbon–carbon bonds, leading to steroid-like molecules with high stereoselectivity in a single step with low catalyst loadings.

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