Ruthenium–indenylidene complexes represent a class of robust and efficient pre-catalysts for olefin metathesis reactions. In this feature article, we provide an overview the various belonging to family summarise their use in applications. The relation between nature ancillary ligands around metal coordination sphere these catalytic activity is also discussed.

Three novel "boomerang" precatalysts bearing different aminocarbonyl functions are reported. Comparative kinetic studies show that this functional group allows for a control of the catalytic activity in metathesis transformations. The scope more active catalyst is investigated and shows good tolerance to various substrates ring-closing metathesis, enyne cross metathesis. ICP-MS analyses illustrate affinity silica gel, as levels Ru contamination lower than 6 ppm detected final products.

Abstract The synthesis and characterization of three novel trifluoromethylamido‐containing “boomerang” precatalysts bearing various N‐heterocyclic carbene (NHC) ligands are reported. Comparative kinetic stability studies show the significant effect NHC on catalyst reaction profile. An investigation scope for diverse metathesis transformations has allowed us to establish influence activity, especially as a function substrate steric bulk. excellent one is disclosed, its recovery at end...

Abstract As depicted in many textbooks, the addition of organometallics to nitriles is generally limited a single addition, providing ketones after acidic hydrolysis. However, double leading tertiary carbinamines also possible, as demonstrated early 1939 by allyl Grignard reagents α‐ethoxyacetonitrile. Since this seminal result, and stimulated biological importance so‐obtained carbinamines, efforts were devoted expand scope nitriles. This review presents these different approaches which have...

The aim of this report is to highlight the latest advances in use N-heterocyclic carbenes (NHCs) as ancillary ligands for transition metal-mediated transformations. A critical overview their scope and performance provided.

The catalytic performances of three Phosphabicyclononane (Phoban)-containing ruthenium-based pre-catalysts have been evaluated for metathesis transformations. A wide screening substrates in ring-closing reactions reveals the greater efficiency pre-catalyst 4. Comparison activities 4 with Grubbs' first-generation illustrates key role Phoban ligand. Additionally, a comparative study Phoban-containing has conducted self-metathesis 1-octene at low catalyst loading (25−100 ppm).

Abstract Efficiency of ionic liquid supported organotin reagents in Stille cross‐coupling reactions involving aryl bromides has been investigated. In a general manner, products were isolated with good yields by using very simple catalytic system without the need solvent, ligand, or additives. The compounds recycled loss activity and contamination tin was limited controlled ([Sn] < 3 ppm).

Abstract A comparative study examining the catalytic activity of a series five indenylidene‐containing ruthenium complexes in olefin cross‐metathesis reactions is presented. Results reveal greater efficiency precatalyst 5 , highlighting key role N,N′ ‐bis(2,6‐diisopropylphenyl)imidazol‐2‐ylidene (IPr) ligand for this transformation. The scope was investigated and several microwave experiments were carried out allowing catalyst loadings as low 0.1 mol%. Overall, products isolated moderate to...

Efficiency of ionic liquid supported organotin reagents in halodemetalation reaction has been investigated.

Well-defined, highly reactive poly(norbornenyl azlactone)s of controlled length (number-average degree polymerization DPn¯ = 10 to 1,000) were made by ring-opening metathesis (ROMP) pure exo-norbornenyl azlactone. These converted into glycopolymers using a facile postpolymerization modification (PPM) strategy based on click aminolysis azlactone side groups amino-functionalized glycosides. Pegylated mannoside, heptyl-mannoside, and pegylated glucoside used in the PPM. Binding inhibition...

A new versatile cyclic polymer platform for the design of advanced materials was prepared by combining ring-expansion metathesis polymerization (REMP) and click chemistry. Cyclic poly(norbornenyl azlactone) backbones were synthesized over an unprecedented length range with number-average degree (DPn) ranging from 25 to 1000. The topology thoroughly characterized using 1H NMR, size exclusion chromatography (SEC) multiangle light scattering (MALS) viscometer detection. Postpolymerization...

Hybrid bidentate phosphoramidite ligands are a recent family of promising phosphorus ligands. The different classes (phosphoramidite-phosphine, phosphoramidite-phosphite, phosphoramidite-phosphinite, phosphoramidite-thioethers, phosphoramidite-amine, phosphoramidite-NHC, phosphoramidite-oxazoline) presented along with the strategies used to access these compounds. main part review summarizes results evaluation in reactions catalyzed by transition metals/bidentate ligands, such as...

The magnificent neutral: Secondary amines are cyclized into the corresponding scalemic pyrrolidines and piperidines with in situ-prepared chiral alkylamido ate neutral yttrium ytterbium catalysts. enantiomeric excess of 83 % ee is highest reported value for a rare-earth-promoted hydroamination secondary amine. Detailed facts importance to specialist readers published as "Supporting Information". Such documents peer-reviewed, but not copy-edited or typeset. They made available submitted by...

Abstract The 1,2‐dianion reactivity of the reagent generated from EtMgBr and titanium isopropoxide was illustrated when N ‐acyl cyanohydrins were used as substrates (>20 examples), giving both aminocyclopropane derivatives 1,4‐dicarbonyl compounds. When reaction performed in diethyl ether, 5‐hydroxy‐1,4‐diketones main product. Under specific conditions (use tetrahydrofuran a bulky carboxylic moiety), cyclopropane obtained good yields. observed dichotomy may be explained by ring‐opening...

A straightforward synthesis of symmetrically α,α-disubstituted α-amino acids is presented. The key step this process relies on the efficient double addition Grignard reagents to acyl cyanohydrins provide <i>N</i>-acyl amino alcohols selectively in good yields. chemoselectivity reaction was modulated by nature moiety. Eleven were prepared, including particularly simple divinylglycine, which not easily accessible using conventional methods.

2-Aminochromene derivatives display important pharmacological properties, including mainly antibiotic and anticancer activities.The study aims to synthesize new chromene via a approach using Grignard reagents, for the evaluation of their antifungal properties.A series novel 3-cyano-4-aminochromene bearing alkyl substituents at 4-position was prepared biological evaluation.These compounds were obtained by addition various reagents into Nethoxycarbonyl- 3-cyanoiminocoumarines in moderate good...

A comparative study of the titanium-mediated cyclopropanation (benzyloxy)acetonitrile and Boc-protected cyanohydrin using unsaturated Grignard reagents (but-3-enyl- pent-4-enylmagnesium bromides) is described. The best conditions to provide <i>cis</i> <i>trans</i> isomers cyclopropylamines bearing unsaturation were identified alkene moiety was subjected chemical modifications, as shown by synthesis orthogonally protected <i>cis</i>- <i>trans</i>-2,3-methanolysine,...

The titanium-catalyzed asymmetric cyclopropanation of cyanoesters­ with Grignard reagents was investigated for the first time. Particularly, study efficiency Taddol-based titanium complexes­ has shown that prior preparation Taddol complexes not required and a large panel ligands evaluated by using this approach. spirocyclopropanelactams were obtained good diastereoselectivity moderate enantioselectivities from main diastereoisomer (up to 32%).

Allylzinc reagents were used to access highly functionalized tertiary carbinamine derivatives in high yields from cyanoesters and cyanocarbonates. While the monoaddition of organometallics on nitriles is generally observed, this work nucleophilic allylation occurs twice, due an intermediate transfer carbonyl moiety onto nitrogen atom. The chemoselectivity reaction allows presence various functionalities case carbonate derivatives, nature final product was modulated by kinetic control, giving...

New oxazolone‐based heteromultifunctional linkers were synthesized using a zinc‐mediated double functionalization of nitriles as the key step. The orthogonality functional groups displayed by this original scaffold was demonstrated conducting sequential or simultaneous multi‐component reactions with amines (oxazolone ring opening), thiols (thiol‐ene radical reaction) and azides (Cu‐catalyzed azide–alkyne coupling), in respect to concept click chemistry.