Synthesis of [2]Rotaxanes by the Copper-Mediated Threading Reactions of Aryl Iodides with Alkynes

Abstract

The catalytic activity of the macrocyclic phenanthroline-copper(I) complex is utilized for the Sonogashira-type reaction to synthesize [2]rotaxanes. Thus, [2]rotaxanes were prepared by reactions between terminal alkynes and aryl iodides in the presence of the macrocyclic copper complex. Bulky substituents were introduced to the substrates to stabilize the rotaxane. The bond-forming reaction proceeded selectively inside the macrocyclic complex so that the rotaxanes could be synthesized.

Metal ions in the synthesis of interlocked molecules and materials

“…In reality the conditions for a successful AT reaction are more stringent as the resulting macrocyclemetal complex must adopt conformations in which the covalent bond formation is stereoelectronically biased towards forming the mechanical bond; if the reaction can take place on one face of the macrocycle then no rotaxane will be produced. Castro-Stephens reactions, 40 Pd-mediated Michael addition 41 and the formation of iodo-triazoles.…”

Syntheses, Structures, and Spectroscopic Properties of 1,10‐Phenanthroline‐Based Macrocycles Threaded by PtC8Pt, PtC12Pt, and PtC16Pt Axles: Metal‐Capped Rotaxanes as Insulated Molecular Wires

“…He has also tethered zinc porphyrins to the macrocyclic components . Leigh and Saito have extended this protocol to other templating metals (Pd, Ni) and types of carbon–carbon bond forming reactions, such as click and Sonogashira cross couplings. These represent possible future means of constructing rotaxanes in which the axles terminate in metal fragments.…”

Phenanthroline based rotaxanes: recent developments in syntheses and applications

“…The Cu-mediated coupling reaction (Sonogashira type reaction) between aryl iodide, 100 and alkyne 45b in presence of macrocycle 11a proceeded at elevated temperature and rotaxane 101 was isolated ( Scheme 35 ). 31 …”