Reactions and Structures of Crystalline Molecular Assembly

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In crystalline molecular assemblysuch as crystalline host-guest inclusion complex, molecules are arraged regularly and then chemical reactions would proceed selectively. When chiral host is used, prochiral guest molecules are arranged in a chiral form in the inclusion complex. Photochemical or thermochemical reactions of the prochiral guest in the inclusion complex would give chiral reaction product. On the other hand, when the inclusion complexation between host and a mixture of isomers occurs selectively, separation of isomers can be carried out by the inclusion complexation. When a chiral host is used, separation of enantiomers can be accomplished. Furthermore, in these crystalline molcular assembly, molecular isomerization such as tautomerism is restricted or frozen, and then one tautomer can be isolated in pure form. In these topics, our collaboration works have been done.1) Achiral oxoamides formed inclusion complex with chiral host compound derived from tartaric acid. Photoirradiation of the inclusion crystal in the solid state gave optically active beta-lactam derivative. In most cases, enantioselectivity of the solid state reaction is very high. Arrangement of the prochiral oxoamide molecules in a chiral form has been studied by X-ray crystal structure analysis. Some other prochiral compounds which have diene grooups are also arrranged in a chiral form in an inclusion crystal with chiral host, and photoirradiation of the crystal gave optically active 2+2 photocyclization product.2) Reaction of an inclusion complex of 2-cyclohexenone and a chiral host derived from tartaric acid with dienophile in the solid state gave optically active Michael addition product. In the solid state reaction, dienophile recognizes the upside and downside of the molecular plane of 2-cyclohexenone.3) Some ammonium salt host compounds included phenole derivatives X-ray crystal structures were studied.