Current Organic Chemistry - Volume 23, Issue 2, 2019

Over the last few decades, transition metal-catalyzed direct C-H activation with the assistance of a coordinating directing group has emerged as an atom- and stepeconomical synthetic tools to transform C–H bonds into carbon-carbon or carbonheteroatom bonds. Although the strategies involving regioselective C–H cleavage assisted by various directing groups have been extensively reviewed in the literature, we now attempt to give an overview of the recent advances on phosphorus-containing functional group assisted C-H activation reactions catalyzed by transition-metal catalysts including mechanistic study and synthetic applications. The discussion is directed towards C-H olefination, C-H activation/cyclization, C-H arylation, C-H amination, C-H hydroxylation and acetoxylation as well as miscellaneous C-H activation.

Magnetic nanoparticles derived from iron oxide, for example, magnetite (Fe3O4) and maghemite (γ-Fe2O3), fulfill most of these requirements, and recent advances in their synthesis give access to size-controlled monodisperse particles. Hybrid magnetic materials have been synthesized from organic compounds and metal or metal oxide nanoparticles and examined as catalysts for the organic synthesis. When the reaction has been completed, the catalysts can be easily separated by simple external magnetic decantation.

N-Heterocyclic architectures are omnipresent in many bioactive natural products, synthetic drugs, and materials science, thus have evoked a vast research interest of academic, as well as industrial chemists. Recently, several efficient methods have been developed for the preparation of various nitrogen-containing compounds with in situ generated 1,2-diaza-1,3-dienes from the easily available precursors including α -haloketohydrazones, α-hydroxyl ketohydrazones, thiadiazole dioxides or their analogues, and other simple hydrazones. These methods are considered powerful tools in the synthesis of five-, six- and seven-membered ring heterocyclic compounds with good to excellent levels of conversions and selectivities. This review mainly summarizes recent advances on the chemistry of construction of versatile N-heterocycles from in situ generated 1,2-diaza-1,3- dienes and presents an extensive summary of the application scopes and limitations of the corresponding cyclization reactions. Moreover, enantioselective approaches are also covered.

Since Geim and co-workers reported their groundbreaking experiments on graphene, research on graphene oxide (GO) and its derivatives has greatly influenced the field of modern physics, chemistry, device fabrication, material science, and nanotechnology. The unique structure and fascinating properties of these carbon materials can be ascribed to their eminent chemical, electronic, electrochemical, optical, and mechanical properties of GO and its derivatives, particularly compared to other carbon allotropes. The present Review aims to provide an overview on the recent developments in the preparation of GO and its derivatives and their applications in organic reactions. We will first outline the synthesis of GO and its derivatives. Then, we will discuss the major sections about their application as stoichiometric and catalytic oxidants in organic reactions, a particular emphasis on the carbon-carbon, carbon-oxygen, and carbon-nitrogen single bond-forming reactions, as well as carbon-oxygen and carbon-nitrogen double bond-forming reactions. Simultaneously, this Review also describes briefly transition metal supported on GO or its derivatives as a catalyst for organic reaction. Lastly, we will present an outlook of potential areas where GO and its derivatives may be expected to find utility or opportunity for further growth and study.

Thioxo, Oxo and Seleno diastereomeric cyclophosphamides containing 1,3,2- dioxaphosphorinane are prepared by a one-step chemical reaction. Their structural determination is carried out by means of Nuclear Magnetic Resonance NMR (31P, 1 H, 13C) and High-Resolution Mass Spectroscopy (HRMS). The conformational study of diastereomeric products is described. Density Functional Theory (DFT) calculations allowed the identification of preferred conformations. Experimental and calculated 31P, 13C, 1H NMR chemical shifts are compared. The molecular structure of the 2-Benzylamino-5-methyl-5- propyl-2-oxo-1,3,2-dioxaphosphorinane (3d) has been determined by means of crystal Xray diffraction methods.