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Analysis and Improvement of an Anion‐Templated Rotaxane Synthesis
Author(s) -
Schalley Christoph A.,
Silva Gabriele,
Nising Carl Friedrich,
Linnartz Petra
Publication year - 2002
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/1522-2675(200206)85:6<1578::aid-hlca1578>3.0.co;2-l
Subject(s) - rotaxane , chemistry , steric effects , nucleophile , ion , combinatorial chemistry , atom (system on chip) , stereochemistry , computational chemistry , molecule , organic chemistry , catalysis , parallel computing , supramolecular chemistry , computer science
A series of new rotaxanes with axles different in length was prepared. Following the synthetic protocol utilizing a known anion template effect ( Scheme 1 ), surprisingly low yields in the order of 2–5% were obtained ( Scheme 3 ), which furthermore significantly depended on the nature of the stopper ( Fig. 1 ). Variations in the synthetic procedures and computational results from Monte Carlo simulations allowed us to analyze the origin of these findings: The rotaxane wheel 3 acts as a noncovalently bound ‘protecting group' for the stopper nucleophile. The protection of the nucleophilic phenolate O‐atom depends much on the steric demands of the stoppers (see 2 vs. 10 ) which induce different conformations of the wheel. Based on this model, an improved synthetic scheme is suggested.