10.1016/j.tetlet.2009.02.090
The study investigates the reactions of various carboxylic acids with xenon difluoride (XeF2) in different reaction environments, specifically in CH2Cl2/Pyrex and CH2Cl2/PTFE. The researchers found that Pyrex acts as an effective heterogeneous catalyst, promoting electrophilic reactions that lead to rearrangement, cyclisation, and cationic products. In contrast, reactions in PTFE primarily result in fluorodecarboxylation, likely via a single electron transfer (SET) mechanism. The study examines six structurally diverse carboxylic acids and shows that the products vary significantly depending on the reaction environment. For instance, in Pyrex, the reaction of 1-adamantanecarboxylic acid with XeF2 yields 1-adamantanol, while in PTFE, it produces 1-fluoroadamantane. The study highlights the profound influence of the reaction vessel material on the mechanism and products of these reactions, providing insights into the formation of intermediate fluoroxenon esters and their subsequent transformations.
10.1016/j.tet.2005.02.063
The research focuses on the synthesis and application of a new type of fluorescent building block, 1-(4-nitrophenoxycarbonyl)-7-pyridin-4-yl indolizine, and its derivatives (1a–d). These compounds incorporate a pyridinoindolizine unit and two potentially reactive sites, making them versatile for further structural modifications. The synthesis involves a 1,3-dipolar cycloaddition reaction using bipyridinium ylides and an activated dipolarophile. The newly synthesized building blocks were then reacted with mono-6-amino-6-deoxy-β-cyclodextrin to produce fluorescent water-soluble hosts (2a–d) in good yields. The sensor properties of these hosts were tested in the presence of 1-adamantanol, showing changes in fluorescence emission. Key chemicals involved in this research include bipyridine, various substituted bromoacetophenones, triethylamine, 4-nitrophenylpropiolate, and β-cyclodextrin. The study highlights the potential of these new fluorescent building blocks for applications in biological and supramolecular recognition fields.