The preparation, structure, and chemistry of hypervalent iodine compounds are reviewed with emphasis on their synthetic application. Compounds of iodine possess reactivity similar to that of transition metals, but have the advantage of environmental sustainability and efficient utilization of natural resources. These compounds are widely used in organic synthesis as selective oxidants and environmentally friendly reagents. Synthetic uses of hypervalent iodine reagents in halogenation reactions, various oxidations, rearrangements, aminations, C–C bond-forming reactions, and transition metal-catalyzed reactions are summarized and discussed. Recent discovery of hypervalent catalytic systems and recyclable reagents, and the development of new enantioselective reactions using chiral hypervalent iodine compounds represent a particularly important achievement in the field of hypervalent iodine chemistry. One of the goals of this Review is to attract the attention of the scientific community as to the benefits of...

Advances in Synthetic Applications of Hypervalent Iodine Compounds

140 years ago Adolf von Baeyer proposed the structure of a heteroaromatic compound which revolutionized organic and medical chemistry: indole. After more than a century, indole itself and the complexity of naturally occurring indole derivatives continue to inspire and influence developments in synthetic chemistry. In particular, the ubiquitous presence of indole rings in pharmaceuticals, agrochemicals, and functional materials are testament to the ever increasing interest in the design of mild and efficient synthetic routes to functionalized indole derivatives. This Review emphasizes the achievements in the selective catalytic functionalization of indoles (C-C bond-forming processes) over the last four years.

Catalytic Functionalization of Indoles in a New Dimension

Late transition metal-catalyzed hydroamination and hydroamidation.

Catalyst-free reactions developed during the last decade and the latest developments in this emerging field are summarized with a focus on catalyst-free reactions in-water and on-water. Various named reactions, multi-component reactions and the synthesis of heterocyclic compounds are discussed including the use of various energy input systems such as microwave- and ultrasound irradiation, among others. Organic chemists and the practitioners of this art both in academia and industry hopefully will continue to design benign methodologies for organic synthesis in aqueous media under catalyst-free conditions by using alternative energy inputs based on fundamental principles.

Benign by design: catalyst-free in-water, on-water green chemical methodologies in organic synthesis

Photoredox catalysis has experienced a revitalized interest from the synthesis community during the past decade. For example, photoredox/Ni dual catalysis protocols have been developed to overcome several inherent limitations of palladium-catalyzed cross-couplings by invoking a single-electron transmetalation pathway. This Perspective highlights advances made by our laboratory since the inception of the photoredox/Ni cross-coupling of benzyltrifluoroborates with aryl bromides. In addition to broadening the scope of trifluoroborate coupling partners, research using readily oxidized hypervalent silicates as radical precursors that demonstrate functional group compatibility is highlighted. The pursuit of electrophilic coupling partners beyond (hetero)aryl bromides has also led to the incorporation of several new classes of C(sp2)-hybridized substrates into light-mediated cross-coupling. Advances to expand the radical toolbox by utilizing feedstock chemicals (e.g., aldehydes) to access radicals that were prev...

Photoredox-Mediated Routes to Radicals: The Value of Catalytic Radical Generation in Synthetic Methods Development

1,2-Dipyridiniumditribromide-ethane (DPTBE) has been synthesized and explored as a new efficient brominating agent. The crystalline ditribromide reagent is stable for months and acts as a safe source of bromine requiring just 0.5 equiv for complete bromination. It has high active bromine content per molecule and shows a remarkable reactivity compared to other tribromide reagents toward various substrates by just grinding the reagent and substrates in a porcelain mortar at room temperature. No organic solvent has been used during any stage of the reaction for substrates giving product as solid. Product can easily be isolated by just washing the highly water soluble 1,2-dipyridiniumdibromide-ethane (DPDBE) from the brominated product. The spent reagent can be recovered, regenerated, and reused without any significant loss.

https://pubs.acs.org/doi/pdf/10.1021/jo0511795

A New Recyclable Ditribromide Reagent for Efficient Bromination under Solvent Free Condition

A facile and rapid synthesis of isocoumarin derivatives using a copper-catalyzed tandem C–C/C–O coupling strategy from readily available substrates is described. The reactions of a wide range of 2-iodo-N-phenyl benzamides and acyclic diketones as starting materials were investigated.

Synthesis of isocoumarin derivatives via the copper-catalyzed tandem sequential cyclization of 2-halo-N-phenyl benzamides and acyclic 1,3-diketones.

A convenient one-pot synthesis of thiazol-2-imines: application in the construction of pifithrin analogues

http://www.sciencemadness.org/talk/files.php?pid=445996&aid=50046

Aqueous-Mediated N-Alkylation of Amines

Stabilization energy, as proposed by Parr and Pearson (J. Am. Chem. Soc., 1983, 105, 7512) is decomposed into fragments. When the donor is not a perfect one and both the donor and the acceptor are ordinary organic molecules this decomposition is shown to provide energy fragments which, individually, can be correlated to the reaction rate of that particular step. It is shown how these different energy fragments can be used, together with the global electrophilicity value of the acceptor (wA), to locate the rate-determining step in multi-step reactions.

A Comprehensive Decomposition Analysis of Stabilization Energy (CDASE) and its application in locating the rate-determining step of multi-step reactions

Veerababurao Kavala

Papers

A New Recyclable Ditribromide Reagent for Efficient Bromination under Solvent Free Condition

Synthesis of isocoumarin derivatives via the copper-catalyzed tandem sequential cyclization of 2-halo-N-phenyl benzamides and acyclic 1,3-diketones.

A convenient one-pot synthesis of thiazol-2-imines: application in the construction of pifithrin analogues

Aqueous-Mediated N-Alkylation of Amines

A Comprehensive Decomposition Analysis of Stabilization Energy (CDASE) and its application in locating the rate-determining step of multi-step reactions