Planar chiral rotaxanes were synthesized from crown ether and secondary ammonium salt via trialkylphosphane-catalyzed acylative end-capping. Their optical resolution was achieved by chiral HPLC after acylative neutralization of the ammonium group. When optically active trialkylphosphane 2 was used as the chiral acylation catalyst, optically active rotaxane (4.4% ee) was obtained.
According to the results of a model study using benzyl alcohol, pseudorotaxane with terminal hydroxy group on the axle was acylated with S-2-pyridyl 3,5-dimethylthiobenzoate in the presence of tributylphosphine to produce rotaxane in 85% yield. Optically active [2]rotaxane and [3]rotaxane were readily synthesized by this method.
Rotaxanes
Rotaxanes O 0450Tributylphosphine-Catalyzed Acylation of Alcohol by Active Ester Directed Toward Effective End-Capping of Pseudorotaxane Consisting of Ammonium Group and Crown Ether. -(KIHARA*, N.; NAKAKOJI, N.; TAKATA*, T.; Chem. Lett. 2002, 9, 924-925; Dep. Appl. Chem., Coll. Eng., Osaka Prefect. Univ.,
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