Woodward-Hoffmann rule

Woodward-Hoffmann rule

[′wu̇d·wərd ′häf·mən ‚rül]
(organic chemistry)
A concept which can predict or explain the stereochemistry of certain types of reactions in organic chemistry; it is also described as the conservation of orbital symmetry.
References in periodicals archive ?
More specifically, it violates the Woodward-Hoffmann rules, which classify permitted reactions based on how much energy it takes to retain the orbital symmetry of the affected atoms.
But now, Philip Power and Yang Peng of the University of California, Davis and colleagues have demonstrated a reaction with tin that is forbidden by the Woodward-Hoffmann rules for carbon.