Hemicarcerands synthesis

Scheme 5. The synthesis of hemicarcerand 16 is temp-lated around a molecule of DMA, leading to the production of hemicarceplex 16-DMA.

Fig. 19 (A) Thermodynamically controlled synthesis of hemicarcerand 37.129,130 (B) The delivery of ferrocene from 34 to bulk solution occurred at a faster rate in the presence of TFA and/or 1,3-diaminobenzene. (For color version of this figure, the reader is referred to the web version of this book.)...

Cram [49a] elaborated further on this concept by enclosing space in his carcerands and hemicarcerands (See Scheme 1) to form a new inner phase which he has referred to as a new phase of matter . In contrast to the hollow space found inside clathrates and zeolites for instance, the cages of these molecules are independent of the form and physical state. For example, hemicarcerands and related supramolecular systems (i.e. hemicarceplexes) prevail in the solid, liquid, or gas phase. This characteristic-hollow space, the inside surface — is maintained across all phase transitions. The inner surfaces and spaces of these systems are not manifested as bulk properties. An extensive review on the synthesis of these materials has been published recently [205]. 

Carcerands 1427-1429—see also Hemicarcerands Carceroisomerism 1430 Carpanone, synthesis of 1311... 

The synthesis of hemicarcerands and carceplexes is a templated reaction and the proper choice of template molecule, which complements the shape and size of the inner cavity... 

Carcerands and Hemicarcerands, p. 189 Concave Reagents, p. i /1 Crown Ethers, p. 326 Cryptophanes, p. 340 Cyclodextrins, p. 398 Cyclodextrins, Applications, p. 405 Cyclophanes Definition and Scope, p. 414 Enzyme Mimics, p. 546 Macrocycle Synthesis, p. 830 Organometallic Anion Receptors, p. 1006 Soft and Smart Materials, p. 1302 X-Ray Crystallography, p. 1586... 

Cryptophanes are related to hemicarcerands - they are composed of smaller and shallower cavitand bowls, such as cyclotriveratrylene (CTV) molecules that have been used for both anion and neutral molecule recognition (Section 2.5.2). The first cryptophane was synthesised in 1981 via a self-directed synthesis. This small cage is named, chronologically, cryptophane-A (2.126) (Figure 2.31). Space-filling models of cryptophane-A show a closed surface container, with... 

Since the first carceplex synthesis, a large variety of hemicarcerands have been prepared by connecting two cavitands with four appropriate linkers, and their binding properties have been studied (Figure These hemicarcerands... 

The two-step synthesis of the novel clam shell hemicarcerand 7 was prepared by known procedures and then shown to be photochemically converted into the carcerand and that 7 in the presence of p-dimethoxy-benzene gave the desired hemicarceplex, in which the guest was encapsulated within the host (13ACIE655). 

Proximally Functionalized Cavitands and Synthesis of a Flexible Hemicarcerand ... 

In contrast to the parent calix[4]arenes, selective functionalization of the resorcinol-based calix[4]arenes [ 18] has hardly been studied. Partly functionalized cavi-tands have only been isolated as side products in the synthesis of tetrafunctionalized cavitands [19, 20]. Although such dissymmetric cavitands have been used in the synthesis of chiral cavitands [21] and hemicarcerands [20] with promising applications [22], their synthesis was never studied in detail. While our work was in progress [23], Sorrell and Richards showed that cavitands can be selectively functionalized at the upper rim by means of a Claisen rearrangement [24]. In this paper we describe the synthesis of partly bridged octols [25] together with a novel route to functionalize these cavitands selectively in a proximal way. 

Barba V, Betanzos I (2007) Direct synthesis of poly-macrocyclic boron compounds a convenient method for the synthesis of hemicarcerands. J Organomet Chem 692 4903-4908... 

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