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An unprecedented hydroalumination of C ═ O bonds catalyzed by zirconocene dichloride is reported herein and applied to the site-selective deprotection of peracetylated functional substrates. A mixed metal hydride, with 1:1 zirconium/aluminum stoichiometry, is also shown to be the reductive species. A catalytic cycle is finally proposed for this transformation with no precedent in the field of zirconium catalysis.

An unprecedented hydroalumination of C ═ O bonds catalyzed by zirconocene dichloride is reported herein and applied to the site-selective deprotection of peracetylated functional substrates. A mixed metal hydride, with 1:1 zirconium/aluminum stoichiometry, is also shown to be the reductive species. A catalytic cycle is finally proposed for this transformation with no precedent in the field of zirconium catalysis.

International audience; A series of organic dyes derived from s-tetrazine have been synthesized, and their photophysical and electrochemical properties are systematically investigated. Testing these compounds as photoredox catalysts in a model oxidative C-S bond cleavage of thioethers has led us to identify new classes of active s-tetrazines. Moreover, some of them can be formed in situ from commercially available 3,6-dichlorotetrazine, making this photocatalyzed C-S bond functionalization simple and highly practical.

International audience; The combined Lewis acid catalytic system, generated from molecular iodine and tritylium tetrafluoroborate effectively catalyzed the Friedel−Crafts (FC) arylation of diarylmethyl sulfides providing an efficient access to various unsymmetrical triarylmethanes. The addition of tritylium and iodine created a more active catalytic system to promote the cleavage of sulfidic C-S bonds. Unsymmetrical triarylmethanes 1 represent an important class of organic molecules due to their occurrence in bioactive natural products (such as muchimangin G-J, 1f melanervin 1k) and pharmaceuticals 1g-i (Figure 1).

An electrochemical intramolecular oxytrifluoromethylation of

International audience; An electrochemical intramolecular oxytrifluoromethylation of N-tethered alkenyl alcohols was developed providing straightforward access to CF3-containing morpholines derivatives. The method features mild reaction conditions with direct anodic oxidation of Langlois reagent as cheap and easy to handle trifluoromethylating reagent. Variously substituted 2-(2,2,2trifluoroethyl)morpholines were obtained in moderate to high yields under constant current electrolysis in an undivided cell.

International audience; Ylide-type reactivity of diazo compounds is exploited in a new way to prepare benzo[b]oxepines thanks to the formation of three chemical bonds and two contiguous and highly substituted stereocenters in a single pot. This cationic reaction cascade first involves addition of a donor–acceptor-substituted diazo compound to a benzopyrylium. Selective 1,2 migration of the endocyclic C–C bond then results in a ring-expansion and generates a second oxocarbenium that is trapped by a nucleophile added sequentially.

A versatile synthesis of azidolactones through azidation and cyclization of carboxylic acids onto alkenes has been developed. Based on either photoredox or palladium catalysis, (1,1) and (1,2) azido lactones can be selectively synthesized. The choice of catalyst and benziodoxol(on)e reagent serving as azide source was essential to initiate either a radical or Lewis acid mediated process with divergent outcome. These transformations were carried out under mild conditions using a low catalyst loading and gave access to a large scope of azido lactones.

International audience; A new organocatalytic and environmentally friendly aerobic oxidative-catalyzed nitroso-Diels-Alder (NDA) reaction of Narylhydroxylamines with dienecarbamates has been developed. 3,6-Bis(2,2,2-trifluoroethoxy)-s-tetrazine) was found to be an effective catalyst to selectively oxidize various N-arylhydroxylamines in the presence of molecular oxygen, but in the absence of photostimulation, as a terminal oxidant. In addition, active catalytic species can be generated in situ from commercially available 3,6-dichlorotetrazine.

International audience; A combination of DIBAL-H and Cp2ZrCl2 is shown to promote the regioselective cleavage of primary acetates on a broad scope of substrates, ranging from carbohydrates to terpene derivatives, with a high tolerance toward protecting groups and numerous functionalities found in natural products and bioactive compounds. Apart from providing highly valuable building blocks in only two steps from biosourced raw materials, this selective de-O-acetylation should also be strongly helpful to solve selectivity issues in organic synthesis.

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.

A new method for the cyanation of thiols and disulfides using cyanobenziodoxol(on)e hypervalent iodine reagents is described. Both aliphatic and aromatic thiocyanates can be accessed in good yields in a few minutes at room temperature starting from a broad range of thiols with high chemioselectivity. The complete conversion of disulfides to thiocyanates was also possible. Preliminary computational studies indicated a low energy concerted transition state for the cyanation of the thiolate anion or radical. The developed thiocyanate synthesis has broad potential for various applications in synthetic chemistry, chemical biology and materials science.

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.

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.

International audience; α-Alkynyl-α′-trimethylsilylhydrazones are used as novel Rh(II)-carbenoids precursors. These new carbenoids have shown very good reactivity in Si−H insertion reactions, leading to original propargylic geminal-bis(silanes) in a two-step sequential process.

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.

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.

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

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 alpha-amino and alpha-oxo acids derived from biomass.

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.

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

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

A highly stereoselective three-component Povarov reaction, catalyzed by (R)- and (S)-BINOL hydrogen phosphate, was achieved for the first time with aminopyrroles and aminopyrazoles as 2-azadiene precursors. A variety of aldehydes, enecarbamates, amino-substituted azines participated in the reaction to afford the tetrahydropyrrolopyridines and tetrahydropyrazolopyridines in good yields with excellent diatereo- and enantioselectivities. A stereochemical model is proposed to account for the observed absolute stereochemistry.

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.

An enantioselective aza-Friedel–Crafts reaction of indoles with γ-hydroxy-γ-lactams using a chiral phosphoric acid catalyst is reported. The approach described herein provides an efficient access to 5-indolylpyrrolidinones in good to quantitative yields and excellent enantioselectivities (up to >99% ee). The results suggest that the reaction may proceed via N-acyliminium intermediates associated with the chiral phosphoric acid anion.

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.

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.