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Dynamic Control of Chiral Space Through Local Symmetry Breaking in a Rotaxane Organocatalyst
Author(s) -
Dommaschk Marcel,
Echavarren Javier,
Leigh David A.,
Marcos Vanesa,
Singleton Thomas A.
Publication year - 2019
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201908330
Subject(s) - rotaxane , chemistry , amide , catalysis , selectivity , stereochemistry , pyrrolidine , supramolecular chemistry , molecule , organic chemistry
We report on a switchable rotaxane molecular shuttle that features a pseudo‐ meso 2,5‐disubstituted pyrrolidine catalytic unit on the axle whose local symmetry is broken according to the position of a threaded benzylic amide macrocycle. The macrocycle can be selectively switched (with light in one direction; with catalytic acid in the other) with high fidelity between binding sites located to either side of the pyrrolidine unit. The position of the macrocycle dictates the facial bias of the rotaxane‐catalyzed conjugate addition of aldehydes to vinyl sulfones. The pseudo‐ meso non‐interlocked thread does not afford significant selectivity as a catalyst (2–14 % ee ), whereas the rotaxane affords selectivities of up to 40 % ee with switching of the position of the macrocycle changing the handedness of the product formed (up to 60 % Δee).