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Remmerswaal WA, Nguyen TT, Han Z, Krasovski Slobodian F, Xiong R, Kessler V, Xu Z, Zhu W, Erdelyi M
Chempluschem 90 (9) e202500252 [2025-09-00; online 2025-08-04]
A previously unrecognized base-mediated rearrangement of a benzylic 1,5-hexadipyridynyl moiety is reported. Upon exposure to base, this structural motif rearranges into a constrained vinyl-pyridine substituted cyclobutene. Computational modeling indicates that the rearrangement takes place following a route involving stepwise deprotonation, shifted reprotonation, and 4π-electrocyclization. The reaction rate and the stereochemical outcome is consistent with the experimental observations. Furthermore, nonbase mediates rearrangements, through well-known Cope-like [3,3]-sigmatropic shifts, are found to be high in energy, and therefore, take a backseat to the base-mediated pathway. This rearrangement may provide a novel reactivity pathway of conjugated systems for synthetic methodology development.
PubMed 40608800
DOI 10.1002/cplu.202500252
Crossref 10.1002/cplu.202500252