A theoretical investigation of endocyclic allylic carbon-centered radical formation in retinoic acid

1997 ◽  
Vol 7 (18) ◽  
pp. 2343-2348
Author(s):  
Victor M. Samokyszyn ◽  
Hebron C. Chang ◽  
R.Lilia Compadre
Keyword(s):  
Retinoic Acid ◽  
Theoretical Investigation ◽  
Radical Formation ◽  
Carbon Centered Radical

CO2 or SO2: Should It Stay or Should It Go?

2019 ◽  
Author(s):  
Gabriel dos Passos Gomes ◽  
Alexander Wimmer ◽  
Joel Smith ◽  
Burkhard König ◽  
Igor Alabugin
Keyword(s):  
Computational Analysis ◽  
Cross Coupling ◽  
Radical Formation ◽  
Structural Effects ◽  
Two Factors ◽  
Carbon Centered Radical ◽  
Dissociative Processes ◽  
Entropy Characteristic

<div><div><div><p>A broad computational analysis of carbon-centered radical formation via the loss of either CO2 or SO2 from the respective RXO2 radical precursors (X = C or S) reveals dramatic differences between these two types of dissociative processes. Whereas the C-C scission with the loss of CO2 is usually exothermic, the C-S scission with the loss of SO2 is generally endothermic. However, two factors can make the C-S scissions thermodynamically favorable: increased entropy, characteristic for the dissociative processes, and stereoelectronic influences of substituents. The threshold between endergonic and exergonic C-S fragmentations depends on subtle structural effects. In particular, the degree of fluorination in a radical precursor has a notable impact on the reaction outcome. This study aims to demystify the intricacies in reactivity regarding the generation of radicals from sulfinates and carboxylates, as related to their role in radical cross-coupling.</p></div></div></div>

scholarly journals CO2 or SO2: Should It Stay or Should It Go?

2019 ◽  
Author(s):  
Gabriel dos Passos Gomes ◽  
Alexander Wimmer ◽  
Joel Smith ◽  
Burkhard König ◽  
Igor Alabugin
Keyword(s):  
Computational Analysis ◽  
Cross Coupling ◽  
Radical Formation ◽  
Structural Effects ◽  
Two Factors ◽  
Carbon Centered Radical ◽  
Dissociative Processes ◽  
Entropy Characteristic

<div><div><div><p>A broad computational analysis of carbon-centered radical formation via the loss of either CO2 or SO2 from the respective RXO2 radical precursors (X = C or S) reveals dramatic differences between these two types of dissociative processes. Whereas the C-C scission with the loss of CO2 is usually exothermic, the C-S scission with the loss of SO2 is generally endothermic. However, two factors can make the C-S scissions thermodynamically favorable: increased entropy, characteristic for the dissociative processes, and stereoelectronic influences of substituents. The threshold between endergonic and exergonic C-S fragmentations depends on subtle structural effects. In particular, the degree of fluorination in a radical precursor has a notable impact on the reaction outcome. This study aims to demystify the intricacies in reactivity regarding the generation of radicals from sulfinates and carboxylates, as related to their role in radical cross-coupling.</p></div></div></div>

scholarly journals Strategic use of amino acid N-substituents to limit α-carbon-centered radical formation and consequent loss of stereochemical integrity

2003 ◽  
Vol 14 (19) ◽  
pp. 2919-2926 ◽  
Author(s):  
Anna K. Croft ◽  
Christopher J. Easton ◽  
Katherine Kociuba ◽  
Leo Radom
Keyword(s):  
Amino Acid ◽  
Radical Formation ◽  
Carbon Centered Radical

scholarly journals CO2 or SO2: Should It Stay or Should It Go

2018 ◽  
Author(s):  
Gabriel dos Passos Gomes ◽  
Alexander Wimmer ◽  
Joel Smith ◽  
Burkhard König ◽  
Igor Alabugin
Keyword(s):  
Computational Analysis ◽  
Cross Coupling ◽  
Radical Formation ◽  
Structural Effects ◽  
Stereoelectronic Effects ◽  
Two Factors ◽  
Carbon Centered Radical ◽  
Dissociative Processes ◽  
Entropy Characteristic

<p>A broad computational analysis of carbon-centered radical formation via the loss of either CO<sub>2</sub> or SO<sub>2</sub> from the respective RXO<sub>2</sub> radical precursors (X = C or S) reveals dramatic differences between these two types of dissociative processes. Whereas the C-C scission with the loss of CO<sub>2</sub> is usually exothermic, the C-S scission with the loss of SO<sub>2</sub> is generally endothermic. However, two factors can make the C-S scissions thermodynamically favorable: increased entropy, characteristic for the dissociative processes, and substituent stereoelectronic effects. The threshold between endergonic and exergonic C-S fragmentations depends on subtle structural effects. In particular, the degree of fluorination in a radical precursor has a notable impact on the reaction outcome. This study aims to demystify the intricacies in reactivity regarding the generation of radicals from sulfinates and carboxylates, as related to their role in radical cross-coupling.</p>

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