Antarafacial

Some articles on antarafacial:

Cycloaddition - Reaction Mechanism
... occur, for reasons of orbital symmetry, in a suprafacial-suprafacial or antarafacial-antarafacial manner (rare) ... for example the cycloaddition) these proceed in a suprafacial-antarafacial sense, such as the dimerisation of ketene, in which the orthogonal set of p orbitals allows the reaction to proceed via ...
Antarafacial And Suprafacial
... Antarafacial and suprafacial are two topological concepts in organic chemistry describing the relationship between two simultaneous chemical bond ... This relationship is antarafacial when opposite faces are involved (think anti) ... Many sigmatropic reactions and cycloadditions can be either suprafacial or antarafacial, and this determines the stereochemistry ...
Woodward–Hoffmann Rules - General Formulation
... in the Generalized Woodward–Hoffmann rules, everything is characterized in terms of antarafacial and suprafacial bond topologies ... A conrotatory reaction mechanism corresponds to an antarafacial bond topology as illustrated in the diagram to the right ... Here, (4q+2)s and (4r)a refer to suprafacial (4q+2)-electron and antarafacial (4r)-electron components, respectively ...
Woodward–Hoffmann Rules - Selection Rules
... The more inclusive bond topology descriptors antarafacial and suprafacial subsume the terms conrotatory and disrotatory, respectively ... Antarafacial refers to bond making or breaking through the opposite face of a π system, p orbital, or σ bond, while suprafacial refers to the process ... at a chiral center preserves stereochemistry, whereas an antarafacial transformation reverses stereochemistry ...
Woodward–Hoffmann Rules - General Formulation - Examples - -Sigmatropic Rearrangement
... If j=4n-1 then it must be antarafacial, and if j=4n+1, then it must be suprafacial ... shifts are generally not observed as the symmetry-allowed antarafacial process is not feasible, but -hydride shifts are quite facile ... For a -alkyl shift, where the reaction can be antarafacial (i.e ...