This review article highlights recent discoveries in synergistic–cooperative combination of enamine catalysis with transition metal catalysis.

Readily available and facilely tunable pyridine N-oxides have been developed as effective photoinduced hydrogen-atom-transfer (HAT) catalysts for site-selective C–H functionalizations of a broad range substrates, including unactivated alkanes. Pyridine N-oxide radicals, catalytically generated from by photoredox catalyzed single-electron oxidation, are the key intermediates that enable an HAT process carbon radical generation to achieve alkylation, amination, azidation, allylation,...

Regioselective carbohydroxylation and aminohydroxylation of α-olefins were developed by a photoredox catalyst pyridine N-oxide. This approach offers the catalytic direct conversion unactivated alkenes to series primary alcohols, including those bearing β-quaternary carbon centers β-amino alcohols. The regioselective difunctionalization is enabled radical addition α-olefin from N-oxy radical, which generated readily available N-oxide via catalyzed single-electron oxidation. A combination...

Radial cracking has been identified as the primary mode of failure in all-ceramic crowns. This study investigates hypothesis that critical loads for radial crown-like layers vary explicitly square ceramic layer thickness. Experimental data from tests with spherical indenters on model flat laminates selected dental ceramics bonded to clear polycarbonate bases (simulating crown/dentin structures) are presented. Damage initiation events video-recorded situ during applied loading, and measured....

Powerful combination: Arylamines and metal Lewis acids are used as catalysts in the highly chemo- enantioselective three-component inverse-electron-demand aza-Diels–Alder reaction of cyclic ketones with enones. The enantioselectivity is introduced by a simple chiral anion (see scheme). can also serve effective enamine combination either acid or Brønsted acid. As service to our authors readers, this journal provides supporting information supplied authors. Such materials peer reviewed may be...

β-Lactam derivatives are produced through intermediate donor-acceptor cyclopropene intermediates in high yield, exclusive cis-diastereoselectivity, and enantiocontrol a chiral dirhodium carboxylate catalyzed intramolecular C-H functionalization reaction of enoldiazoacetamides.

Abstract The first asymmetric [3+1]‐cycloaddition was successfully achieved by copper(I) triflate/double‐sidearmed bisoxazoline complex catalyzed reactions of β‐triisopropylsilyl‐substituted enoldiazo compounds with sulfur ylides. This methodology delivered a series chiral cyclobutenes in good yields high enantio‐ and diastereoselectivities (up to 99 % ee , >20:1 d.r.). Additionally, the catalytically generated metallo‐enolcarbenes extended reaction stable benzylidene dichlororuthenium complex.

Chiral cyclopentane-fused indolines are synthesized with high regio- and enantiocontrol by formal [3 + 2]-annulation reactions of indoles electrophilic enol carbenes. High enantioselectivity exclusive regiocontrol occurred enoldiazoacetamides using a less sterically encumbered prolinate-ligated dirhodium(II) catalyst in N-substituted without substituents at the 2- or 3-positions via selective vinylogous addition process. In this transformation, donor–acceptor cyclopropenes generated from...

Dirhodium(II) catalysts have proven effectiveness in controlling selectivity metal carbene reactions of diazocarbonyl compounds. Over the years many dirhodium(II) paddlewheel derivatives with chiral ligands been advanced, but three structural classes emerged as being most effective for inducing high stereocontrol: dirhodium carboxamidates derived from cyclic carboxamides and carboxylic acids sybstituted prolinates or phthalimide-protected α-amino acids. This review focuses on describing...

Highly selective divergent cycloaddition reactions of enoldiazo compounds and α-diazocarboximides catalyzed by copper(I) or dirhodium(II) have been developed. With tetrakis(acetonitrile)copper(I) tetrafluoroborate as the catalyst epoxypyrrolo[1,2-a]azepine derivatives were prepared in good yields excellent diastereoselectivities through first reported [3+3]-cycloaddition a carbonyl ylide. Use Rh2 (pfb)4 (esp)2 directs reactants to regioselective [3+2]-cycloaddition generating...

Catalyst-dependent [4 + 2]-cycloaddition reactions of azoalkenes from α-halohydrazones with enol diazoacetates have been developed. A in situ formed produces tetrahydropyridazinyl-substituted promoted by only Cs2CO3. In contrast, donor–acceptor cyclopropenes, which are Rh2(OAc)4-catalyzed dinitrogen extrusion, undergo to yield bicyclo[4.1.0]tetrahydropyridazines. These stable cycloaddition products subsequent one-step transformations form 6-alkylidenetetrahydropyridazines and...

Abstract The all‐ cis stereoisomers of tetrasubstituted azetidine‐2‐carboxylic acids and derivatives that possess three chiral centers have been prepared in high yield stereocontrol from silyl‐protected Z‐γ‐substituted enoldiazoacetates imido‐sulfur ylides by asymmetric [3+1]‐cycloaddition using sabox copper(I) catalysis followed Pd/C catalytic hydrogenation. Hydrogenation the p ‐methoxybenzyl azetine‐2‐carboxylates occurs with both hydrogen addition to C=C bond hydrogenolysis ester.

The bis(imino)pyridine iron complex, for the first time, is developed as an effective metal carbene catalyst transfer reactions of donor–acceptor diazo compounds.

Donor–acceptor cyclopropenes are formed quantitatively or in high yield from enoldiazoacetates and enoldiazoacetamides under moderate thermal conditions.

Catalyst effectiveness for metal carbene formation and reactions has been surveyed using N-(tert-butyl)-3-[(tert-butyldimethylsilyl)oxy]-2-diazo-N-(4-chlorobenzyl)but-3-enamide in the of products from both intramolecular C–H insertion aromatic cycloaddition. Both are indicators intermediates, this system provides a means to assess catalysts formation. Donor–acceptor cyclopropene production reactant enoldiazoacetamide monitored its formation, independently formed also used Catalysts...

A photocatalyzed ortho-alkylation of pyridine N-oxide with ynamides and arylacetylenes has been developed, which yields a series α-(2-pyridinyl) benzyl amides/ketones. Mechanistic studies, including electrochemical radical-trapping experiments, Stern-Volmer fluorescence quenching studies demonstrate that serves as both redox auxiliary radical acceptor to achieve the mild photocatalytic single-electron oxidation carbon-carbon triple bonds generation cationic vinyl intermediate.

The first photoinduced synthesis of polyfunctionalized 3-aza[<italic>n</italic>.1.0]bicycles from readily available ene-ynamides and 2,6-lutidine <italic>N</italic>-oxide using an organic acridinium photocatalyst is reported.

The aim of this study was to evaluate the dentinal tubule occluding ability tricalcium silicate (Ca(3) SiO(5) or C(3) S) in vitro.Dentine discs were prepared from extracted caries-free human third molars and etched with 0.02 M citric acid (pH 4) for 3 minutes order produce patent tubules. Tricalcium pastes different viscosities applied surface dentine specimens then removed a swab followed by deionized water rinse. immersed artificial saliva 7 days. occlusion, sealing depth chemical...

A Sc(OTf)3-catalyzed three-component cyclization reaction of arylamines, β,γ-unsaturated α-ketoesters and 1,3-dicarbonyl compounds was developed to synthesize highly substituted 1,4-dihydropyridines fused bicyclic tetrahydropyridines carrying a quaternary all-carbon center.

Chiral cyclopentyl β-amino esters are formed catalytically by [3+2] cycloaddition reactions of enecarbamates with electrophilic metalloenolcarbenes in high yield up to 98 % ee and excellent diastereocontrol. Use β-silyl-substituted enoldiazoacetates a chiral dirhodium catalyst trans-β-arylvinylcarbamates optimal for this transformation, which occurs hydrogen-bond association between the vinylcarbamate intermediate metalloenolcarbene. Reductive conversion protected amino forms highly...

Proteolysis-targeting chimera (PROTAC) drugs rely on the formation of a ternary complex consisting target protein, drug, and ubiquitin-protein ligase (E3 ubiquitin ligase). However, some cancer patients may not exhibit sufficient expression both protein E3 in tumor tissues, leading to potential off-target effects when treated with conventional PROTACs. In this study, we have developed photoactivated PROTAC strategy that employs photosensitizer monosubstituted amino phthalocyanine (ZnPc)...