| Abstract
| - Irradiation of 2-benzoyladamantane derivatives in zeolites yields the endo-cyclobutanols as theonly photoproduct via a γ-hydrogen abstraction process. The cyclobutanols readily undergo retro-aldol reaction to give δ-ketoesters. The enantiomeric excess (ee) in the endo-cyclobutanols ismeasured by monitoring the ee in the ketoesters. Whereas in solution the ee in the product ketoesteris zero, within achiral NaY zeolite, in the presence of a chiral inductor such as pseudoephedrine,ee's up to 28% have been obtained. The influence of zeolite on several chiral esters of 2-benzoyladamantane-2-carboxylic acids has also been examined. Whereas in solution the diastereomericexcess is <15%, in zeolite the δ-ketoesters are obtained in 79% de (best examples). Ab initiocomputations suggest that enhancement of chiral induction within zeolites is likely to be due tocation complexation with the reactant ketone. Alkali ion-organic interaction, a powerful tool, iswaiting to be fully exploited in photochemical and thermal reactions. In this context zeolites couldbe a useful medium as one could view them as a reservoir of “naked” alkali ions that are onlypartially coordinated to the zeolite walls.
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