Host-guest inclusion chemistry

Alternative strategies to improve MTO-catalyzed oxidations have made use of host-guest inclusion chemistry [45-47]. It was found that a urea/hydrogen peroxide (UHP) complex is a very effective oxidant in heterogeneous alkene epoxida-... 

Scheme 2. Preparation of chiral - 01 (S j-2,2 -bis(diphenyphosphino)-1,1 -binaphthyl.

Alternative strategies to improve MTO-catalyzed oxidations have made use of host-guest inclusion chemistry [46-51]. 

T. J. Ward, Chiral Separations, Anal. Chem. 2002, 74, 2863 J. Hern6ndez-Benito, M. P. Garda-Santos, E. O Brien, E. Calle, and J. Casado, A Practical Integrated Approach to Supramolecular Chemistry IE. Thermodynamics of Inclusion Phenomena, J. Chem. Ed. 2004, 81, 540 B. D. Wagner, P. J. MacDonald, and M. Wagner, Visual Demonstration of Supramolecular Chemistry Fluorescence Enhancement upon Host-Guest Inclusion, J. Chem. 

Fig. 1 Definitions and overall scheme of supramolecular events (a) chemical host synthesis and formation of a supramolecule (host-guest inclusion compound) (b) endo- and exosupramolecular receptor-substrate (host-guest) chemistry and (c) formation of mono-and multimolecular inclusion compounds.

They are particularly attractive in Host-Guest Complex Chemistry because of their ability to form inclusion complexes with ions or/and neutral molecules, so they can function as ion and neutral molecule receptors in which the shape and the dimension of the cavity determine the selectivi toward the guest, 4... 

Fig. 9. Cucurbituril inclusion chemistry (a) tridimensional stmcture of cucurbit[6]uril (b) conjectured cross-sectional representation of a host—guest...

It is not easy to control the steric course of photoreactions in solution. Since molelcules are ordered regularly in a crystal, it is rather easy to control the reaction by carrying out the photoreaction in a crystal. However, molecules are not always arranged at an appropriate position for efficient and stereoselective reaction in their crystals. In these cases inclusion chemistry is a useful technique, as it can be employed to position molecules appropriately in the host-guest structure. Chiral host compounds are especially useful in placing prochiral and achiral molecules in suitable positions to yield the desired product upon photoirradiation. Some controls of the steric course of intramolecular and intermolelcular photoreactions in inclusion complexes with a host compound are described. 

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