Catalytic "Active-Metal" template synthesis of [2]rotaxanes, [3]rotaxanes, and molecular shuttles, and some observations on the mechanism of the Cu(I)-catalyzed azide-alkyne 1,3-cycloaddition

Vincent Aucagne, Jose Berna, James D. Crowley, Stephen M. Goldup, Kevin D. Haenni, David A. Leigh, Paul J. Lusby, Vicki E. Ronaldson, Alexandra M. Z. Slawin, Aurlien Viterisi, D. Barney Walker

Research output: Contribution to journalReview articlepeer-review

202 Citations (Scopus)

Abstract

A synthetic approach to rotaxane architectures is described in which metal atoms catalyze covalent bond formation while simultaneously acting as the template for the assembly of the mechanically interlocked structure. This "active- metal" template strategy is exemplified using the Huisgen-Meldal-Fokin Cu(l)catalyzed 1,3-cycloaddition of azides with terminal alkynes (the CuAAC "click" reaction). Coordination of Cu(I) to an endotopic pyridine-containing macrocycle allows the alkyne and azide to bind to metal atoms in such a way that the metal-mediated bond-forming reaction takes place through the cavity of the macrocycle-or macrocycles-forming a rotaxane. A variety of mono- and bidentate macrocyclic ligands are demonstrated to form [2]rotaxanes in this way, and by adding pyridine, the metal can turn over during the reaction, giving a catalytic active-metal template assembly process. Both the stoichiometric and catalytic versions of the reaction were also used to synthesize more complex two-station molecular shuttles. The dynamics of the translocation of the macrocycle by ligand exchange in these two-station shuttles could be controlled by coordination to different metal ions (rapid shuttling is observed with Cu(l), slow shuttling with Pd(II)). Under active-metal template reaction conditions that feature a high macrocycle:copper ratio, [3]rotaxanes (two macrocycles on a thread containing a single triazole ring) are also produced during the reaction. The latter observation shows that under these conditions the mechanism of the Cu(l)-catalyzed terminal alkyne-azide cycloaddition involves a reactive intermediate that features at least two metal ions.

Original languageEnglish
Pages (from-to)11950-11963
Number of pages14
JournalJournal of the American Chemical Society
Volume129
DOIs
Publication statusPublished - 3 Oct 2007

Keywords

  • SITU CLICK CHEMISTRY
  • BENZYLIC AMIDE
  • TERMINAL ALKYNES
  • TRANSLATIONAL ISOMERISM
  • CYCLOADDITION REACTION
  • INTERLOCKED STRUCTURES
  • ELECTRODE SURFACES
  • ARYL CHLORIDES
  • ROTAXANES
  • POLYROTAXANES

Fingerprint

Dive into the research topics of 'Catalytic "Active-Metal" template synthesis of [2]rotaxanes, [3]rotaxanes, and molecular shuttles, and some observations on the mechanism of the Cu(I)-catalyzed azide-alkyne 1,3-cycloaddition'. Together they form a unique fingerprint.

Cite this