Unravelling Supramolecular Photocycloaddition: Cavitand-Mediated Reactivity of 3-(Aryl)Acrylic Acids

J Photochem Photobiol A Chem. 2022 Mar 1:425:113695. doi: 10.1016/j.jphotochem.2021.113695. Epub 2021 Dec 1.

Abstract

The supramolecular photocycloaddition (PCA) of 3-(phenyl)acrylic acid has been extensively pursued by chemists to study weak interactions and synthesize substituted cyclobutanes. The stereo- and regioselectivity of the products in a supramolecularly affected reaction are often used as a probe for assessing the nature of weak interactions and/or molecular ambience of the reactants. However, some crucial aspects of this chemistry have often remained underexplored in the past, especially within the context of interpreting strength and directionality of interactions based on reaction outcomes. We present a detailed study of the cavitand-mediated PCA of a new and suitable reactant (3-(naphthyl)acrylic acids) that exhibits labile photo-reversible chemistry, which is suitable for exploring previously un-explored aspects of the supramolecular PCA chemistry. Our studies afford important insights about this chemistry that should be considered while using product selectivity as a proxy for deducing intermolecular interactions.

Keywords: Photocycloaddition; cucurbituril; cyclodextrin; host-guest chemistry; supramolecular chemistry; truxillic acid; truxinic acid.