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Updated: Oct 11, 2025
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Solid-phase Synthesis of [4.4] Spirocyclic Oximes
Published on: February 6, 2019
Breathing Room: Restoring Free Rotation in a Schiff-Base Macrocycle through Endoperoxide Formation
Mohammad T Chaudhry1, Seiya Ota1, Francesco Lelj2
1Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, British Columbia V6T 1Z1, Canada.
Abstract:
Macrocyclization is a popular method for preparing hosts, but it can have unintended effects, like limiting molecular free rotation to yield mixtures of inseparable isomers. We report a [3 + 3] Schiff-base macrocycle (1) with anthracene bridges. Restricted rotation about the phenyl-anthracene bonds leads 1 to exist as a mixture of conformations (1 and 1). Macrocycle 1 was photooxidized to tris(endoperoxide) adduct 4, alleviating restricted rotation. These results were supported by spectroscopic, structural, and computational analyses.
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