Sleeping Beauties in Chemistry. Oosterhoff, Havinga and Schlatmann: Four Years Before “The Woodward‐Hoffmann Rules”† **

Several forerunners to the Woodward‐Hoffmann rules appear in the chemical literature in the early 1960s. While these precedents refer to orbital symmetry and explain either electrocyclic reactions (Luitzen Oosterhoff, cited by Egbert Havinga and Jos Schlatmann in Tetrahedron in 1961) or some cycloaddition reactions (Kenichi Fukui, in a book chapter published in 1964), they did not attract any attention and did not serve to initiate any research prior to the publication of the five Woodward and Hoffmann communications in 1965. Even Woodward and Hoffmann were unaware of these precedents (though Hoffmann knew of Fukui's frontier orbital theory) until after they had completed the relevant portions of their work. The Oosterhoff‐Havinga‐Schlatmann story will be told in this paper; the Fukui story will be told in the next paper in this series on the history of the development of the Woodward‐Hoffmann rules. Explanations for these precedents not being productive in solving the no‐mechanism problem are discussed.