Diradical ring closing reactions displaying Woodward–Hoffmann behaviour and torquoselectivity

RSC Advances ◽  
2015 ◽  
Vol 5 (38) ◽  
pp. 30405-30408 ◽  
Author(s):  
Roberto Villar López ◽  
Olalla Nieto Faza ◽  
Carlos Silva López
Keyword(s):  
Closed Shell ◽  
Shell Structures

The applicability of the Woodward–Hoffmann rules seems to expand beyond classical closed shell structures.

Synthesis of Metallic Nanoparticles Using Closed-Shell Structures as Templates

2018 ◽  
Vol 13 (4) ◽  
pp. 362-372 ◽  
Author(s):  
Li Qiu ◽  
Ryan McCaffrey ◽  
Wei Zhang
Keyword(s):  
Metallic Nanoparticles ◽  
Closed Shell ◽  
Shell Structures

Closed-shell structures and the building game

1987 ◽  
Vol 141 (6) ◽  
pp. 478-484 ◽  
Author(s):  
David J. Wales
Keyword(s):  
Closed Shell ◽  
Shell Structures

scholarly journals Electronic communication in phosphine substituted bridged dirhenium complexes – clarifying ambiguities raised by the redox non-innocence of the C4H2- and C4-bridges

2016 ◽  
Vol 45 (13) ◽  
pp. 5783-5799 ◽  
Author(s):  
Yan Li ◽  
Olivier Blacque ◽  
Thomas Fox ◽  
Sandra Luber ◽  
Walther Polit ◽  
...  
Keyword(s):  
Electronic Communication ◽  
Closed Shell ◽  
Shell Structures ◽  
Rhenium Complexes ◽  
Dirhenium Complexes

Dinuclear rhenium complexes with C4H2- or C4- bridges can show open or closed shell structures.

Hydrostibination of Alkynes: A Radical Mechanism

2020 ◽  
Author(s):  
Josh MacMillan ◽  
Katherine Marczenko ◽  
Erin Johnson ◽  
Saurabh Chitnis
Keyword(s):  
Density Functional ◽  
Activation Barrier ◽  
Closed Shell ◽  
Reaction Rates ◽  
Radical Mechanism ◽  
Neutral Radical ◽  
Kinetic Isotope ◽  
Rate Limiting Step ◽  
Ionic Mechanisms ◽  
Terminal Acetylenes

The addition of Sb-H bonds to alkynes was reported recently as a new hydroelementation reaction that exclusively yields anti-Markovnikov <i>Z</i>-olefins from terminal acetylenes. We examine four possible mechanisms that are consistent with the observed stereochemical and regiochemical outcomes. A comprehensive analysis of solvent, substituent, isotope, additive, and temperature effects on hydrostibination reaction rates definitively refutes three ionic mechanisms involving closed-shell charged intermediates. Instead the data support a fourth pathway featuring neutral radical Sb<sup>II</sup> and Sb<sup>III</sup> intermediates. Density Functional Theory (DFT) calculations are consistent this model, predicting an activation barrier that is within 1 kcal mol<sup>-1</sup> of the experimental value (Eyring analysis) and a rate limiting step that is congruent with experimental kinetic isotope effect. We therefore conclude that hydrostibination of arylacetylenes is initiated by the generation of stibinyl radicals, which then participate in a cycle featuring Sb<sup>II</sup> and Sb<sup>III</sup> intermediates to yield the observed <i>Z</i>-olefins as products. This mechanistic understanding will enable rational evolution of hydrostibination as a methodology for accessing challenging products such as <i>E</i>-olefins.

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