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Polyether Natural Product Inspired Cascade Cyclizations: Autocatalysis on π‐Acidic Aromatic Surfaces
Author(s) -
Paraja Miguel,
Hao Xiaoyu,
Matile Stefan
Publication year - 2020
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.202000681
Subject(s) - autocatalysis , chemistry , catalysis , cascade reaction , hexafluorobenzene , cascade , delocalized electron , computational chemistry , combinatorial chemistry , stereochemistry , organic chemistry , molecule , chromatography
Anion‐π catalysis functions by stabilizing anionic transition states on aromatic π surfaces, thus providing a new approach to molecular transformation. The delocalized nature of anion–π interactions suggests that they serve best in stabilizing long‐distance charge displacements. Aiming therefore for an anionic cascade reaction that is as charismatic as the steroid cyclization is for conventional cation‐π biocatalysis, reported here is the anion‐π‐catalyzed epoxide‐opening ether cyclizations of oligomers. Only on π‐acidic aromatic surfaces having a positive quadrupole moment, such as hexafluorobenzene to naphthalenediimides, do these polyether cascade cyclizations proceed with exceptionally high autocatalysis (rate enhancements k auto / k cat >10 4 m −1 ). This distinctive characteristic adds complexity to reaction mechanisms (Goldilocks‐type substrate concentration dependence, entropy‐centered substrate destabilization) and opens intriguing perspectives for future developments.