Key points are not available for this paper at this time.
4Rotaxanes featuring three axles threaded through a single ring have been prepared through active metal template synthesis. Nickel-catalyzed sp(3)-sp(3) homocouplings of alkyl bromide "half-threads" through 37- and 38-membered 2,2':6',2″-terpyridyl macrocycles generate triply threaded 4rotaxanes in up to 11% yield. An analogous 39-membered macrocycle produced no rotaxane products under similar conditions. The constitutions of the 4rotaxanes were determined by NMR spectroscopy and mass spectrometry. Doubly threaded 3rotaxanes were also obtained from the reactions but no 2rotaxanes were isolated, suggesting that upon demetalation the axle of a singly threaded rotaxane can slip through a macrocycle that is sufficiently large to accommodate three threads.
Danon et al. (2016) studied this question.