Organic ring-closing reactions often yielded baffling mixtures of chemical isomers that defied classical thermodynamic rules; Robert Woodward and Roald Hoffmann proved that orbital symmetry dictates exactly which molecular shapes can form. By tracking how electron phases overlap during thermal and photochemical reactions, the Woodward-Hoffmann rules gave chemists complete geometric control over complex molecular synthesis.
During the golden age of synthetic medicine, when chemists attempted to synthesize complex antibiotics and anticancer compounds, chemical reactions produced bizarre, unpredictable mixtures of mirror-image molecules. Heating a flask produced one shape, while shining ultraviolet light produced the exact opposite, baffling synthetic chemists for decades.
Woodward and Hoffmann proved that electron clouds have distinct mathematical wave phases that must stay aligned during a reaction. Like interlocking gears that can only rotate in coordinated directions to keep their teeth aligned, reacting atoms must twist together to keep positive and negative electron waves smoothly connected.
These orbital symmetry rules gave chemists complete control over the geometry of matter. By eliminating trial-and-error in life-saving drug synthesis, by enabling the total synthesis of Vitamin B12 and cancer drugs, and by unlocking the geometry of complex organic molecules, orbital symmetry transformed chemistry.
Stereochemistry of Electrocyclic Reactions
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTStereochemistry of Electrocyclic ReactionsR. B. Woodward and Roald HoffmannCite this: J. Am. Chem. Soc. 1965, 87, 2, 395–397Publication Date (Print):January 1, 1965Publication History Published online1 May 2002Published inissue 1 January 1965https://pubs.acs.org/doi/10.1021/ja01080a054https://doi.org/10.1021/ja01080a054research-articleACS PublicationsRequest reuse permissionsArticle Views8017Altmetric-Citations1186LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose Get e-Alerts
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