Macrobicycles synthesis

Shortly after their first report of all-oxygen bridged cryptands, Dietrich, Lehn and Sauvage reported incorporation of sulfur in the strands. The experimental methods used were essentially similar to those applied in the syntheses of the parent cryptands. As in previous cases, a diacyl chloride was condensed with a diamine under high dilution conditions. In this case, however, the diamine contained sulfur atoms rather than oxygen. The synthesis of compound 5 was accomplished in two stages as illustrated below in Eq. (8.3). The first cyclization step affords the macrocyclic amine in 55% yield. The macrobicyclic product (5) is formed in 25% yield from the monocyclic diamine and the acid chloride. 

Complexes containing encapsulated metal ions (clathrochelates ) with the formula [M(dioxime)3(BR)2] are known with iron(II) 135, cobalt(ll) 136, cobalt(III) 137, and ruthenium(ll) 138 (Fig. 37) [205-220]. Generally, these macrobicyclic complexes are prepared by template synthesis from a mixture of... 

Lehn and coworkers52 reported the synthesis, crystal structure and dinuclear copper(I) complexes of tris-carotenoid macrobicyclic ligands. The macrobicycles 89 and 90 were obtained in good yields in a one-step macrobicyclisation condensation between the tripode N(CH2CH2NH2)3 and the polyolefinic dialdehydes 93 and 94. 

J. P. Konopelski, F. Kotzyba-Hibert, J.-M. Lehn, J.-P. Desvergne, F. Fages, A. Castellan, and H. Bouas-Laurent, Synthesis, cation binding, and photophysical properties of macrobicyclic an-thraceno-cryptands,./. Chem. Soc., Chem. Commun. 433 (1985). 

An ingenious synthesis led to the production of macrobicyclic ligands, one of which, (XXII), has six oxygen and two nitrogen atoms as potential donors. Crystal structure determination of RbNCS (XXII), H2O (104),... 

Work by Newcomb et al. has resulted in the synthesis of a number of macrocyclic and macrobicyclic host molecules somewhat related to the katapinands (vide supra) containing two Lewis acidic chloro-substituted tin centers separated by macrocyclic... 

Martell et al. (33g) while studying the complex equilibria of a new octaaza macrobicyclic cryptand, (MX)3(tren)2 (containing two tren moieties and three m-xylyl groups) reported the synthesis and... 

Various approaches have been taken to the synthesis of effective luminescent materials, using a variety of large encapsulating antenna-containing ligands, including podands, calixarenes, macrocycles, and macrobicycles (cryptands). These have been divided into acyclic (sub-section A) and cyclic (sub-section B). Representative ligands and complexes will be presented and discussed. 

Dietrich, B., Dilworth, B., Lehn, J.-M., etal, Anion cryptates Synthesis, crystal structures, and complexation constants of fluoride and chloride inclusion complexes of polyammonium macrobicyclic ligands. Helv. Chim. Acta 1996, 79, 569-587. 

The use of metal ions as kinetic synthetic templates is extremely widespread, and is an excellent way in which to bring about the organisation of a number of reacting components in order to direct the geometry of the product. Because some metal ions, such as the transition metals, often have preferred coordination geometries (e.g. tetrahedral, square planar, octahedral etc), changes in metal ion may have a profound effect on the nature of the templated product. Metal-ion-templated syntheses may be classified more generally as examples of self-assembly with covalent postmodification. For example, the synthesis of the artificial siderophore 10.2 is effected by the use of an octahedral Fe3+ template.8 In this case, the macrobicyclic product is obtained as the Fe3+ complex from which it is difficult to separate. 

Chen, D. Martell, A. E. The synthesis of new binuclear polyaza macrocyclic and macrobicyclic... 

Lehn, J.-M. Pine, S. H. Watanabe, E. I. Willard, A. K. Binuclear cryptates. Synthesis and binuclear cation inclusion complexes of bis-tren macrobicyclic ligands, J. Am. Chem. Soc. 1977, 99, 6766-6768. 

The synthesis of macropolycyclic cryptands generally involves stepwise, straightforward pathways (18, 20, 33) based on the successive construction of systems of increasing cyclic order macrocyclic, macrobicyclic, and so on. Newkome has recently reported a satisfactory quaternization-dealkylation procedure, facilitating the synthesis of 8 (34). Unlike the synthetic approaches to simple crown ethers (10,... 

Lehn120) has also reported the synthesis of a lateral macrobicyclic molecule, 193, where a macrocyclic unit is bridged by a chelating unit which contains a... 

The cryptands were first prepared in 1969 and form a series of well-defined complexes (cryptates) with alkali and alkaline-earth cations. In this chapter the synthesis of the first cryptand, 8, a macrobicyclic ligand, will be described1,2. The schematic representation (Fig. 5.1) shows that one deals with a multi-step synthesis. The major drawback of this approach is the rather large number of synthetic steps, but the route offers the advantage of being able to construct unsymmetrical compounds (A B C). 

In order to gain more direct access to these bicyclic ligands, methods have been developed which allow the formation of the macrobicycle in one step. The tripod-tripod coupling is an example of this method (Fig. 5.2) which may be performed without the need for high-dilution conditions. The synthesis of the bis-tren macrobicycle, 17, illustrates this approach.3... 

The construction of the macrobicyclic system is shown in Scheme 5.1. The acyclic starting materials are the diacid chloride 2 and the diamine 3.4 An alternative synthesis of the intermediate monocycle is given in Chapter 2 (Protocol 5). 

The following procedure for the synthesis of macrobicycle 6 is representative of a high dilution reaction. 

The first reported synthesis of this compound involved the stepwise procedure described in Scheme 5.8.5 One can note that there are two cyclization reactions which were accomplished in 59% and 60% yields. The synthesis required ten steps and the overall yield was 7%. In order to gain more direct access to the macrobicyclic compound a shorter route involving a tripod-tripod coupling sequence was developed (Scheme 5.9). 

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