Asymmetric induction with cyclodextrins: Photocyclization of tropolone alkyl ethers

Employing the photobehavior of tropolone alkyl ethers as the probe, we have established that cyclodextrins could as a serve as medium to bring about enantioselective photoreactions. The enantioselectivity observed in this study is moderate at best. The enantioselectivity observed in the solid state in comparison to aqueous solution suggests that a rigid environment may be essential to achieve chiral induction during photoreactions of organic molecules. In this context the much higher enantioselectivity observed for the same systems within zeolites is noteworthy. (C) 2000 Elsevier Science Ltd.