Catenane high-yield synthesis

Mohr B, Week M, Sauvage J-P, Gmbbs RH. High-yield synthesis of [2]catenanes by intramolecular ring-closing metathesis. Angew Chem Int Ed Engl 1997 36 1308-1310. 

Chen et al. proved 30 separately binds both 5 and 14 in 1 1 and 1 2 stoichiometries <20060L211, 20060L1859>. Chen et al. used X-ray crystallography for definitive proof of their high-yielding synthesis of the [4]catenane of 32 with 3equiv of 15 (Figure 7). A catenane is a set of mechanically linked mactocycles. 

Figure 9.9 High-yielding synthesis of "Sauvage-type" symmetrical catenane 26 [89].

It was not only for the basic scientific knowledge but also for the new challenges in the synthesis and the beauty of the final structures that nearly half a century ago, chemists started to investigate intertwined macrocyclic supramolecules such as rotaxanes and catenanes [4], Earlier, when the syntheses of such structures were at their infancy, the routes to such systems were troublesome. The statistical methods [5] proved to be low-yield processes. Multistep procedures [6] involving a covalent junction which is formed between two parts that are needed to stay together until the structure is complete were not convenient as well. The use of non-covalent templates thus provided a more straightforward and high-yield approach to the problem. 

Takata et al. reported another very interesting amide-based poly[2]catenane (or oligo[2]catenane) 19 (Scheme 17.8) [57]. Here, the [2]catenane monomer 18 was synthesized in a high yield by utilizing macrocycle-1 as a template (this has proven to be a good templating precursor for the synthesis of catenanes) [56, 82]. Poly[2]catenane 19 was prepared via the Diels-Alder polymerization of 18 at 140°C, without solvent, for several hours. According to GPC analysis with... 

The spectacularly high yield of the [2]catenane is a testament to the efficiency of the template-directed route to its synthesis. In acetonitrile, the [BBIPYXY] dication and BPP34C10 exist in a noninteractive state. However, the addition of BBB results in the formation of a highly coloured solution. The reason is as follows. Once the first m rmolecular Sn2 reaction has occurred to form the trication (Scheme 3), the mutual recognition (for example, by the emerging K—n stacking interactions) between the components ensures that the second intramolecular Sn2 reaction to afford the [2]catenane, proceeds rapidly via a favoured transition state to the cooperatively assembled molecule. The relatively fast rate of the final cyclisation step is illustrated by the fact that the 1 1 complex between the tricationic species and BPP34C10 has not been detected in the reaction mixture. 

In 1995 Leigh et al. reported a catenane synthesis that is convincing not only because of its simplicity but also because it is accessible to a wide variety of reactants [24]. When isophthaloyl dichloride (3) was reacted with l,4-bis(aminometh-yl)benzene at high dilution [2]catenane 28 was isolated in 20% yield without further purification by column chromatography (Figure 13). 

The amide-based template synthesis of rotaxanes, catenanes and knots were first discovered by Vogtle and coworkers when they tried to synthesize macrocycle 3 [13], The cyclization to yield the tetralactam ring was carried out under high-dilution... 

Fig. 27 Examples of thermodynamically controlled reactions employed in the near-quantitative synthesis of MIMs. (a) Disulfide-exchange reaction permits equilibration between a bis(ammo-nium) disulfide dumbbell and a crown ether macrocycle to yield a mixture of [2]- and [3]rotaxanes quantitatively [194], (b) Olefin metathesis at high concentration on a benzylic amide macrocycle greatly favors the catenated species [196]. (c) Self-correcting imine bonds allow for nearly quantitative selection of a [2]rotaxane from an appropriate dynamic combinatorial library [76], (d) A weak nucleophile (E) equilibrates the components of a donor-acceptor [2]catenane in a dynamic Sn2 reaction [205]...

Physical properties of these poly[2] catenaries have been explored in expectation of unique properties based on the catenane structure [239, 246]. While various interesting physical properties were found in polyrotaxane, no characteristic property has been reported in [2]catenanes so far. Although poly[2]catenane has highly mobile moiety due to the mechanical bond, it has been suggested that the connection between [2]catenane subunit restricted the mobility in motion of [2]catenane. Further, intramolecular interaction in [2]catenane subunit may decrease its mobility. Secondary amide-based [2]catenanes can easily be prepared from commercially available compounds. Takata et al. found that the borane-reduction of the [2]catenanes afforded good yields of the amine-based [2]catenanes that can be useful for polymer synthesis [247, 148] (Scheme 51). Although the origi-... 

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