The Many Chemists Who Could Have Proposed the Woodward‐Hoffmann Rules (Including Roald Hoffmann) But Didn't: The Theoretical and Physical Chemists^†**

Abstract

It is a reasonable question to ask, why, as of 1965 when the five Woodward‐Hoffmann communication appeared, did no other physical chemist or chemical physicist or theoretical chemist discover the orbital symmetry rules for all pericyclic reactions? Two theoretical chemists – Luitzen Oosterhoff (in 1961) and Kenichi Fukui (in 1964) had discovered portions of the orbital symmetry rules; their stories appear in the papers immediately preceding this paper which is Paper 5 in a 27‐paper series on the history of Woodward‐Hoffmann rules. Concise yet telling stories of 19 other chemists who could have, might have, perhaps even should have discovered the Woodward‐Hoffmann rules are presented with explanations as to why they did not do so. Social, political, and scientific explanations will summarize the analyses.

Introduction to “The Woodward‐Hoffmann Rules. From May 5, 1964, to November 30, 1964”**

“…Publication 5 discusses 19 such chemists and discusses those chemists could have but did not solve the pericyclic no-mechanism problem. [32] These 19 stories are particularly interesting because of their subjects' idiosyncratic backgrounds and experiences. Included among these chemists are several Americans who used the MOs of conjugated systems in their own research (e. g., R. 10.…”

“…[35] Other chemists discussed in Publication 7 include Arthur Cope, namesake of one of the prototypical examples of nomechanism reactions; Paul D. Bartlett, one of the top physical organic chemists of the era who published extensively on the nonconcerted 2 + 2 cycloadditions; Derek Barton, the discoverer of conformational analysis; John D. Roberts and Andrew Streitwieser, both of whom wrote textbooks on MO theory for organic chemists that were published in 1961; [36,37] and Michael J. S. Dewar who discovered perturbation molecular orbital theory in 1951 [38][39][40][41][42][43] and antiaromaticity in 1965. [44] * Publications 5, [32] 6 [45] and 7 [46] discuss the many chemists who were so very close to discovering the WÀ H rules but did not do so. Publications 8 [47] and 9 (in two parts [48,49] ) discuss the two chemists who did so.…”

Revolutions in Chemistry: Assessment of Six 20th Century Candidates (The Instrumental Revolution; Hückel Molecular Orbital Theory; Hückel’s 4n + 2 Rule; the Woodward–Hoffmann Rules; Quantum Chemistry; and Retrosynthetic Analysis)

“…Whether arrow pushing and reasoning by analogy, steric effects, stereoelectronic effects, and conformational analysis, none of those heuristic models or any combination of them could (or can) explain the no-mechanism problem. An entirely new type of mechanism was needed though that was not obvious at the time to the practitioners. − And that mechanistic requirement was an application of quantum chemistry.…”

“…One major example: the solution to the no-mechanism problem discussed in section was not immediately forthcoming. Even those organic chemists who knew of the no-mechanism problem and also knew some measure of quantum chemistry, even those chemists did not think of and publish a quantum chemical solution. − These chemists included Jerome Berson, Breslow, William G. Dauben, Charles DePuy, Dewar, Doering, Roberts, and Zimmerman, all eventual members of the U.S. National Academy of Sciences, and several of whom ,,, had written books on quantum chemistry!…”

My first and my latest publication

“…The Chemists Who Could Have Proposed the Woodward-Hoffmann Rules (Including Woodward and Hoffmann) But Didn't: The Theoretical and Physical Chemists [14] 6…”