Vudvard i Hofman su razvili pravila periciklične selekcije ispitujući korelacije između orbitala reaktanata i proizvoda (tj. kako su orbitale reaktanata i proizvoda međusobno povezane neprekidnim geometrijskim distorzijama koje su funkcije koordinata reakcije). Oni su identifikovali očuvanje orbitalne simetrije kao ključni teorijski princip koji diktira ishod (ili izvodljivost) pericikličkog procesa. Unaprieđeni su i drugi teorijski pristupi koji dovode do istih pravila selekcije. Hofman je 1981. dobio Nobelovu nagradu za hemiju za razjašnjavanje važnosti orbitalne simetrije u pericikličnim reakcijama, koju je delio sa Keničijem Fukuijem. Fukui je razvio sličan skup ideja u okviru granične molekularne orbitalne teorije (FMO). Pošto je Vudvard umro dve godine pre toga, nije imao pravo da dobije ono što bi bila njegova druga Nobelova nagrada za hemiju.[6]
Reference
^The principle of orbital symmetry conservation is generally credited to Robert Burns Woodward and Roald Hoffmann, who proposed orbital symmetry conservation as an explanation for the stereochemical outcome of electrocyclic reactions (J. Am. Chem. Soc.1965, 87, 395) and articulated a fully generalized pericyclic selection rule several years later (Angew. Chem. Int. Ed. Engl.1969, 8, 781). However, E. J. Corey has claimed priority in proposing the key insight in 1965 (see 'Controversy' section below). Moreover, E. Havinga had previously noted that tachysterol underwent electrocyclic ring closing in a conrotatory or disrotatory manner depending on activation mode (photochemical or thermal, respectively) and attributed an orbital symmetry explanation for this phenomenon to L. J. Oosterhoff (Tetrahedron Lett.1961, 16, 146). In addition, aromatic transition state theory, advanced by H. E. Zimmerman (J. Am. Chem. Soc.1966, 88, 1564) and M. J. S. Dewar (Tetrahedron1966, Suppl. 8, 75), has been recognized as an alternative approach that is completely equivalent to, but predates, Woodward and Hoffmann's statement of the generalized rule.
^Ene reactions are often considered to be a type of group transfer reaction.
^Cheletropic reactions are often considered to be a type of cycloaddition.
^Reetz, Manfred T. (1972-02-01). „Dyotropic Rearrangements, a New Class of Orbital-Symmetry Controlled Reactions. Type I”. Angewandte Chemie International Edition in English (на језику: енглески). 11 (2): 129—130. ISSN1521-3773. doi:10.1002/anie.197201291.
^Geerlings, Paul; Ayers, Paul W.; Toro-Labbé, Alejandro; Chattaraj, Pratim K.; De Proft, Frank (2012). „The Woodward–Hoffmann Rules Reinterpreted by Conceptual Density Functional Theory”. Accounts of Chemical Research. 45 (5): 683—95. PMID22283422. doi:10.1021/ar200192t. hdl:10533/131820.
Ayers, Paul W.; Morell, Christophe; De Proft, Frank; Geerlings, Paul (5. 10. 2007). „Understanding the Woodward–Hoffmann Rules by Using Changes in Electron Density”. Chemistry: A European Journal. 13 (29): 8240—8247. PMID17639522. doi:10.1002/chem.200700365.CS1 одржавање: Формат датума (веза)