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Radical difunctionalizations of alkenes constitute an efficient method for the construction of complex organic molecules. This synopsis focuses on visible-light catalysis, a recent and very promising technological refinement of this class of transformations. Examples taken from the literature illustrate the use of a variety of (metallic or nonmetallic) systems, which allow us to leverage the energy of readily available visible-light radiation to efficiently create some of the most commonly looked for types of bonds (C–X, C–O, C–N, and C–C) under mild conditions and starting from unsaturated substrates.

The rapid and regioselective synthesis of a series of 2,6-disubstituted dihydropyranic building-blocks bearing an oxygenated side chain is described. The corresponding 4-iodo tetrahydropyran precursors, easily prepared by Prins cyclization, underwent regioselective elimination in the presence of an In(OAc)3/LiI system to provide the title compounds. The one-pot Prins cyclization-elimination process was also studied and could be achieved with the TMSBr/LiI/In(OAc)3 system.

Chiral phosphoric acid-catalyzed asymmetric nitroso-Diels–Alder reaction of nitrosoarenes with carbamate-dienes afforded cis-3,6-disubstituted dihydro-1,2-oxazines in high yields with excellent regio-, diastereo-, and enantioselectivities. Interestingly, we observed that the catalyst is able not only to control the enantioselectivity but also to reverse the regioselectivity of the noncatalyzed nitroso-Diels–Alder reaction. The regiochemistry reversal and asynchronous concerted mechanism were confirmed by DFT calculations.

Alkynes are used as building blocks in synthetic and medicinal chemistry, chemical biology, and materials science. Therefore, efficient methods for their synthesis are the subject of intensive research. Herein, we report the direct synthesis of alkynes from readily available carboxylic acids at room temperature under visible-light irradiation. The combination of an iridium photocatalyst with ethynylbenziodoxolone (EBX) reagents allowed the decarboxylative alkynylation of carboxylic acids in good yields under mild conditions. The method could be applied to silyl-, aryl-, and alkyl- substituted alkynes. It was particularly successful in the case of α-amino and α-oxo acids derived from biomass.

A new synthetic route to thiadiazolylaminoglycosides, by a ring expansion/ring contraction sequence of glycosyl triazines, has been developed. Two potential mechanisms of this oxidative ring contraction using [TBA-Ox] are discussed. The more plausible involves formation of an oxatriazepane intermediate followed by loss of formic acid, ring opening, and subsequent recyclization.

Enamides and enecarbamates are versatile building blocks in organic synthesis. This review describes the development of enamide chemistry and the utility of the resulting products in the synthesis of a variety of important, biologically active molecules. 1 Introduction 2 Asymmetric Hydrogenation of Enamides 3 Monofunctionalization of Enamide Derivatives 3.1 Palladium-Catalyzed α-Functionalization of Enamide Derivatives 3.2 Ruthenium-Catalyzed β-Functionalization of Enamide Derivatives 4 Ionic Vicinal Difunctionalization of Enamide Derivatives 4.1 Tandem Difunctionalization of Enamide Derivatives 4.2 Cycloadditions 4.2.1 [4+2] Cycloadditions 4.2.2 [2+2] Cycloadditions 4.2.3 Cyclopropanation of Enamides 4.3 Other Pericyclic Reactions 4.3.1 Electrocyclization Reactions 4.3.2 Overman Rearrangement 4.4 Platinum-Catalyzed Vicinal Difunctionalization of Enamide Derivatives 5 Radical Vicinal Difunctionalization of Enamide Derivatives 6 Oxidative Vicinal Difunctionalization of Enamide Derivatives 7 N-Arylation of Enecarbamates 8 Conclusion 9 Ligand Glossary

A new method for the cyanation of thiols (I), (VI), and disulfides (IX) using cyanobenziodoxol(on)e hypervalent iodine reagents, such as (II) and (VII) is described.

The replacement of fossil fuels by a clean and renewable energy source is one of the most urgent and challenging issues our society is facing today, which is why intense research has been devoted to this topic recently. Nature has been using sunlight as the primary energy input to oxidise water and generate carbohydrates (solar fuel) for over a billion years. Inspired, but not constrained, by nature, artificial systems can be designed to capture light and oxidise water and reduce protons or other organic compounds to generate useful chemical fuels. This tutorial review covers the primary topics that need to be understood and mastered in order to come up with practical solutions for the generation of solar fuels. These topics are: the fundamentals of light capturing and conversion, water oxidation catalysis, proton and CO2 reduction catalysis and the combination of all of these for the construction of complete cells for the generation of solar fuels.

Protected α-alkyl lanthionine derivatives were synthesized in five steps starting from a known phenyloxazoline precursor. This approach involved the synthesis of a family of substituted cyclic sulfamidates and their regioselective opening by nucleophilic attack with a protected cysteine. This efficient multistep strategy affords various α-alkylated lanthionine derivatives in high yields.

The developed Povarov reaction proceeds with high enantioselectivity and high diastereoselectivity.

The design of novel antitumor agents allowing the destruction of malignant cells while sparing healthy tissues is one of the major challenges in medicinal chemistry. In this context, the use of non-toxic prodrugs programmed to be selectively activated by beta-glucuronidase present at high concentration in the microenvironment of most solid tumors has attracted considerable attention. This review summarizes the major progresses that have been realized in this field over the past ten years. This includes the new prodrugs that have been designed to target a wide variety of anticancer drugs, the prodrugs employed in the course of a combined therapy, the dendritic glucuronide prodrugs and the concept of β-glucuronidase-responsive albumin binding prodrugs.

5-Aryl-substituted annulated pyridines can be accessed directly from the corresponding acetylene substituted pyrimidines through an intramolecular inverse-electron-demand hetero -/ retro -Diels–Alder ( ih DA/ r DA) reaction cascade carried out in continuous flow. Exploiting this new process, a series of cycloalka[ c ]pyridines that represent useful building blocks for medicinal chemistry were prepared in good to excellent yields with short processing times (

The direct synthesis of cycloalka[c]pyridines via the title reaction by using continuous flow reaction conditions is developed.

The reaction tolerates a wide range of substituents on the indole aromatic ring but is sensitive to the steric effects at the C2-position [cf.

Different 9-aryl-6-chloropurines are synthesized, to some extent by microwave-assisted reactions.

Key features of the approach are the wide substance scope, short reaction times, high atom-economy (no side products) and good to excellent chemical yields.

Both base-assisted non-concerted (nCMD) and concerted metallation—deprotonation (CMD) reactions are identified as potent operating mechanisms in palladoim-catalyzed direct C—H couplings of oxazole and thiazole-4-carboxylates with halides.

Diethyl carbonate and propylene carbonate are good solvents for Pd-catalyzed arylation of a variety of heterocyclic compounds, e.g. benzoxazole, oxazoles, thiazoles, furans, thiophenes, and pyrroles.

Vitamin B12 is an essential vitamin for human health, and lack of it leads to pernicious anemia. This biological activity has attracted intense interest for some time; in addition, the complex architecture of the B12 molecule has fascinated chemists and biochemists since its discovery as the first natural organocobalt complex and the establishment of its structure by X-ray analysis. The organic ligand surrounding the cobalt displays many stereogenic centers along its periphery carrying reactive functional groups. This complexity led vitamin B12 to be rightly regarded as an extreme challenge to the synthetic chemist. Yet microorganisms achieve this synthesis in vivo with complete control of regio- and stereochemistry. How do they do it? This review tells the full remarkable story. Success in unraveling this biosynthetic puzzle resulted from a collaborative effort by biologists and chemists using the full range of methods available from their disciplines–from genetics at one end of the spectrum to synthesis and NMR spectroscopy at the other. This work can act as a guide for future research on the biosynthesis of yet more complex natural substances.

The first palladium-catalyzed borylation of 4-bromo-2-ketothiazoles followed by a Suzuki cross-coupling reaction with haloheteroaromatics using Buchwald’s Cy-JohnPhos and XPhos ligands is reported. The methodology has allowed the fast preparation of highly valuable 4-pyridinyl- and 4-thiazolyl-2-ketothiazoles as common subunits of thiopeptide antibiotics. As direct applications, novel concise syntheses of a sulfomycinamate thio-analogue as well as micrococcinate and saramycetate esters are described.

While achieving high Curie temperatures (above room temperature) in diluted magnetic semiconductors remains a challenge in the case of well controlled homogeneous alloys, several systems characterized by a strongly inhomogeneous incorporation of the magnetic component appear as promising. Incorporation of manganese into germanium drastically alters the growth conditions, and in certain conditions of low temperature Molecular Beam Epitaxy it leads to the formation of well organized nanocolumns of a Mn-rich material, with a crystalline structure in epitaxial relationship with the Mn-poor germanium matrix. A strong interaction between the Mn atoms in these nanocolums is demonstrated by x-ray absorption spectroscopy, giving rise to a ferromagnetic character as observed through magnetometry and x-ray magnetic circular dichroism. Most interesting, intense magneto-transport features are observed on the whole structure, which strongly depend on the magnetic configuration of the nanocolumns.

A straightforward route toward 2-(hetero)arylated and 2,5-di(hetero)arylated oxazoles through regiocontrolled palladium-catalyzed direct (hetero)arylation of ethyl oxazole-4-carboxylate with iodo-, bromo-, and chloro(hetero)aromatics followed by a two-step hydrolysis/decarboxylation sequence was described. The method was applied here to a neat synthesis of two 2,5-di(hetero)aryloxazole natural products, balsoxin and texaline.

International audience; We have examined the reactions of 1,3-disubstituted isobenzofurans with the fullerene C60 in the context of an approach to open a large orifice on the fullerene framework. A variety of substituted isobenzofurans (6a-h), generated from the reaction of 1,4-substituted 1,4-epoxynaphthalenes 3a-h with 3,6-bis(2- pyridyl)-1,2,4,5-tetrazine (4a) or 1,2,4,5-tetrazine (4b), were added to C60 to afford the Diels-Alder adducts 7a-h. The thermal stability of these adducts toward retro-Diels-Alder fragmentation differs greatly in solution from that in the solid state. In solution, the relatively facile retro-Diels-Alder fragmentation of monoadducts 7a and 7c, to give C60 and the free isobenzofurans 6a and 6c, have rate constants (and activation barriers) of k ) 9.29 10-5 s-1 at 70 °C (Ea ) 32.6 kcal mol-1) and k ) 1.36 10-4 s-1 at 40 °C (Ea ) 33.7 kcal mol-1), respectively, indicating that the addition of isobenzofurans to C60 is readily reversible at those temperatures. In the solid state, thermogravimetric analysis of adduct 7a indicates that its decomposition occurs only within the temperature range of 220-300 °C. As a result, these compounds can be stored at room temperature in the solid state for several weeks without significant decomposition but have to be handled within several hours in solution.