Uranyl uptake into metal-organic frameworks: a detailed X-ray structural analysis.

Metal-organic frameworks (MOF) are a subclass of porous framework materials that have been used for a wide variety of applications in sensing, catalysis, and remediation. Among these myriad applications is their remarkable ability to capture substances in a variety of environments ranging from benign to extreme. Among the most common and problematic substances found throughout the world's oceans and water supplies is [UO], a common mobile ion of uranium, which is found both naturally and as a result of anthropogenic activities, leading to problematic environmental contamination.

General Synthetic Approach for the Laurencia Family of Natural Products Empowered by a Potentially Biomimetic Ring Expansion.

The Laurencia family of C-acetogenins is Nature's largest collection of halogenated natural products, with many of its members possessing a brominated 8-membered cyclic ether among other distinct structural elements. Herein, we demonstrate that a bromonium-induced ring expansion, starting from a common tetrahydrofuran-containing bicyclic intermediate and using the highly reactive bromenium source BDSB (EtSBr·SbClBr), can lead to concise asymmetric total syntheses of microcladallenes A and B, desepilaurallene, laurallene, and prelaureatin. Key advances in this work include (1) the first demonstration that the core bromonium-induced cyclization/ring-expansion can be initiated using an enyne with an internal ether oxygen nucleophile, (2) that reasonable levels of stereocontrol in such processes can be achieved both with and without appended ring systems and stereogenic centers, (3) that several other unique chemoselective transformations essential to building their polyfunctional cores can be achieved, and (4) that a single, common intermediate can lead to five different members of the class encompassing two distinct 8-membered cyclic ether ring collections.