Active template rotaxane synthesis through the Ni-catalyzed cross-coupling of alkylzinc reagents with redox-active esters

Research output: Contribution to journalArticle

  • External authors:
  • Javier Echavarren
  • Malcolm A.Y. Gall
  • Adrian Haertsch
  • Vanesa Marcos
  • Daniel J. Tetlow

Abstract

The synthesis of unsymmetrical axle [2]rotaxanes through a recently developed Ni-catalyzed C(sp3)-C(sp3) cross-coupling of redox-active esters (formed directly from carboxylic acids) and organozinc reagents (derived from alkyl bromides) is reported. The method also furnishes, as a minor product, the symmetrical axle [2]rotaxanes resulting from the homo-coupling of the organozinc half-thread. The rotaxanes are formed in up to 56% yield with the ratio of unsymmetrical rotaxane increasing with the cavity size of the macrocycle. In the absence of the redox-active ester neither rotaxane is formed, even though the homo-coupling rotaxane product does not incorporate the redox-active ester building block. A Ni(iii) intermediate is consistent with these observations, providing support for the previously postulated mechanism of the Ni-catalyzed cross-coupling reaction.

Bibliographical metadata

Original languageEnglish
Pages (from-to)7269-7273
Number of pages5
JournalChemical Science
Volume10
Issue number30
Early online date19 Jun 2019
DOIs
Publication statusPublished - 2019