Dienaminodioate based multicomponent reactions with post-benzylic oxidative transformations mediated by DDQ

Multi-Component Reactions in Protein Modification and Immobilization

Protein modification/immobilization has been introduced as a large toolbox for creating a myriad of engineered proteins with profound implications for various scientific and industrial applications. Proteins immobilization techniques are generally performed through protein fixation in/to heterogeneous materials or via inter cross-linking of protein molecules, enabling the development of biocatalysts, biosensors, and drug delivery systems. On the other hand, chemical modification of proteins offers tailored changes in their functionality, enhances protein performance, extends their shelf life, and enables their specific binding interactions. The choice of immobilization or modification technique depends on the significance of various factors for the final product. Chemical coupling methods that create covalent bonds are commonly used for both proposes. Multi-component reactions are particularly effective because they operate under mild conditions to maintain protein functionality while simultaneously introducing multiple functional groups. This review provides an overview of multi-component reactions employed for the immobilization and modification of proteins.

Solid-state synthesis of polyfunctionalized 2-pyridones and conjugated dienes

Functionalized 2-pyridones are important biologically active compounds, DNA base analogues and synthetic intermediates. Herein, we report a simple, green, solid-state synthesis of differently substituted 2-pyridones. It starts from commercially available amines and activated alkynes, uses silica gel (15%Cs2CO3/SiO2) as the solid phase and a reaction vial as the only equipment. If necessary, heating is performed in a laboratory oven. Since most reactions are completed within a few hours, no additional energy consumption is required. The syntheses do not require solvents and other reagents and are easily monitored by standard analytical techniques. The atom economy is high, since all atoms of reactants are present in the products and EtOH is the only by-product. The syntheses produce polyfunctionalized conjugated dienes as the only intermediates, which are also important building blocks.

Synthetic applications of hydride abstraction reactions by organic oxidants

Carbon-hydrogen bond functionalizations provide an attractive method for streamlining organic synthesis, and many strategies have been developed for conducting these transformations. Hydride-abstracting reactions have emerged as extremely effective methods for oxidative bond-forming processes due to their mild reaction conditions and high chemoselectivity. This review will predominantly focus on the mechanism, reaction development, natural product synthesis applications, approaches to catalysis, and use in enantioselective processes for hydride abstractions by quinone, oxoammonium ion, and carbocation oxidants. These are the most commonly employed hydride-abstracting agents, but recent efforts illustrate the potential for weaker ketone and triaryl borane oxidants, which will be covered at the end of the review.