Tomoya Sawaki, K. Endo, Kenji Kobayashi
Dec 1, 1997
Citations
0
Influential Citations
14
Citations
Journal
Bulletin of the Chemical Society of Japan
Abstract
5,5′-(9,10-Anthracenediyl)diresorcinol (1) (host) and a terpenoid aldehyde citronellal (2, guest) form a 1 : 2 adduct 1·2(2), in which the guest molecules hydrogen-bonded to the host are closely packed in an extended conformation in the microporous crystal structure of the host. When heated in vacuo, the 1 : 2 adduct loses ca. 1 molecule of the guest to give a 1 : 1 adduct 1·2. The guest 2 included in both adducts undergoes a facilitated intra-adduct ene reaction to afford isopulegol as the main product. Such a reaction in the 1 : 1 adduct occurs smoothly and in a highly stereoselective (ca. 98%) manner. The reaction in the 1 : 2 adduct is less stereoselective and exhibits a sigmoidal progression curve having a significant “induction period”. The present ene reaction of citronellal (2) as either a neat liquid or in a cyclohexane solution is catalyzed by host 1 in the solid state. The allosteric cooperativity observed is discussed in view of a big conformational change associated with the present cyclizati...