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Phosphazene base, P2-tBu, efficiently catalyzed the telescopic three-component reaction of diethyl phosphite, cinnamonitrile derivatives, and N-Boc imines, providing β-aminophosphonates having a tetrasubstituted carbon in a highly diastereoselective manner. The reaction involves the little-known 1,1-difunctionalization of an electron-deficient alkene, offering a new format for the three-component reaction under Brønsted base catalysis. [ABSTRACT FROM AUTHOR]

Visible light-induced radical umpolung chemistry is utilized to synthesize trifluoromethylated unnatural a-amino acid and amine derivatives. This approach utilizes photoredox catalysis to perform a single-electron-transfer reduction of imines generating a N-centred radical that eventually migrates to the C-centre followed by a radical-radical cross-coupling to deliver reductive trifluoro-methylation products. [ABSTRACT FROM AUTHOR]

Herein, we report an example of a stereoselective γ-addition reaction of trifluoromethyl ketimines to 1-alkynyl ketones mediated by an isothiourea, BTM, under mild conditions, which afforded tetrasubstituted allenes with central chiralities in high yields (up to 94% yield), good enantioselectivities (up to 91% ee), and excellent diastereoselectivities (all >20 : 1 dr). In addition, the BTM-catalyzed γ-addition reaction was successfully applied to the gram-scale reaction, and an unexpected benzopyrrolothiazine derivative was successfully converted, albeit racemic. [ABSTRACT FROM AUTHOR]

Pd-catalyzed sequential intramolecular annulation/intermolecular [3+2] cycloaddition of 5-allenyloxazolidine-2,4-diones with dipoles was achieved. Under palladium catalysis, various 5-allenyloxazolidine-2,4-diones reacted with 1,3-dipoles such as nitrile N-oxides, azomethine imines or nitrilimines to give a series of functionalized spiroheterocycles in high yields. The scale-up reaction and further derivation of products were successful. A plausible mechanism was also proposed based on the control experiments. [ABSTRACT FROM AUTHOR]

Adducts of sterically hindered tellurium catecholate Te(Cat36)2 (Cat36 = 3,6-di-tert-butyl-catecholate) with diimine ligands were isolated and characterized by means of single crystal X-ray diffraction along with IR, UV-vis-NIR and NMR (1H, 125Te) spectroscopy. Adducts with 1,10-phenanthroline (phen) and 5,6-epoxy-5,6-dihydro-[1,10]phenanthroline (phenO) feature a very rare μ-κ2N,N′:κ2N,N′-bridging coordination mode of diimines. The adduct with 2,2′-bipyrimidine (bpm) is dimeric with a μ-κ2N,N′:κ2N,N′-bridging coordination mode of bpm, while with 4,7-dimethyl-1,10-phenanthroline (phenMe2) a dimer is formed due to Te-(η6-C6) contacts. Te⋯N and Te⋯C interactions between Te(Cat36)2 and the diimines were found to be attractive and non-covalent (DFT and QTAIM). In accordance with the weakness of Te⋯N interactions, no ligand-to-ligand charge transfer (LLCT) bands were observed in the electronic spectra of the adducts. [ABSTRACT FROM AUTHOR]

The asymmetric catalytic synthesis of 1,2-diamines has received considerable interest, especially in the last ten years, due to their presence in biologically active compounds and their applications for the development of synthetic building blocks, chiral ligands and organocatalysts. Synthetic strategies based on C–N bond-forming reactions involve mainly (a) ring opening of aziridines and azabenzonorbornadienes, (b) hydroamination of allylic amines, (c) hydroamination of enamines and (d) diamination of olefins. In the case of C–C bond-forming reactions are included (a) the aza-Mannich reaction of imino esters, imino nitriles, azlactones, isocyano acetates, and isothiocyanates with imines, (b) the aza-Henry reaction of nitroalkanes with imines, (c) imine–imine coupling reactions, and (d) reductive coupling of enamines with imines, and (e) [3+2] cycloaddition with imines. C–H bond forming reactions include hydrogenation of C＝N bonds and C–H amination reactions. Other catalytic methods include desymmetrization reactions of meso-diamines. [ABSTRACT FROM AUTHOR]

A catalytic asymmetric vinylogous aldol reaction between β,γ-unsaturated amides and isatins has been developed. In the presence of 10 mol% of tertiary amine-thiourea C7, the vinylogous reaction has been achieved in up to 98% yield and up to 99% ee (26 examples). This methodology provides an efficient approach to construct chiral multifunctional 3-hydroxy-2-oxindoles. Moreover, the transformations of the chiral products, including the esterification of amides, the hydrogenation of the C–C double bond and further conversion to spirolactones, have been investigated. [ABSTRACT FROM AUTHOR]

The document is the contents list for an issue of the journal Chemical Communications. It includes the titles and authors of various articles and features that will be included in the issue. Some of the topics covered include silk-based intelligent fibers and textiles, advances in molecular engineering of perovskite heterostructures, and metal-organic framework based self-powered devices for human body energy harvesting. The journal is published by The Royal Society of Chemistry, a leading chemistry community. [Extracted from the article]

A highly efficient asymmetric [3+2] and [4+2]-annulation of cyclic N-sulfonyl ketimines with γ- or δ-hydroxy-α,β-unsaturated ketones has been developed. This innovative reaction employs an organocatalytic approach, utilizing a hydrogen-bonding bifunctional squaramide-based catalyst. The process enables precise synthesis of chiral polyheterotricyclic oxazolidines and 1,3-oxazinane derivatives, revealing intricate structures with incorporated chiral quaternary centers. Remarkably, this method delivers high yields and exceptional enantioselectivities and diastereoselectivities, achieving up to 99% yield, >20 : 1 dr, and >99% ee. [ABSTRACT FROM AUTHOR]

Catalyst-free annulations of 2-(4H-benzo[d][1,3]oxazin-4-yl)acrylates have been successfully achieved under mild conditions. Specifically, the reaction of 2-(4H-benzo[d][1,3]oxazin-4-yl)acrylates with sulfur ylides furnished various 1,2-dihydroquinolines in generally high yields. Furthermore, [3+2]-annulations of 2-(4H-benzo[d][1,3]oxazin-4-yl)acrylates with α,β-unsaturated imines afforded a broad scope of polysubstituted 2,3-dihydropyrroles with high efficiency. [ABSTRACT FROM AUTHOR]

Herein, we disclose an eco-efficient redox-neutral iron-catalyzed decarboxylative radical addition to chiral azomethine imines upon visible light (427 nm) giving cyclic hydrazine derivatives with dr ranging from 82 : 18 to >96 : 4. This earth-abundant metal promoted sequence proceeds efficiently under ligand-free conditions based on a LMCT process and opens a route to new chiral heterocycles. [ABSTRACT FROM AUTHOR]

Thioglycoside bond formation via an asymmetric sulfa-Michael/aldol reaction of (E)-β-nucleobase acrylketones and 1,4-dithiane-2,5-diol has been achieved with a cinchona alkaloid-derived bifunctional squaramide chiral catalyst. Diverse purine, benzimidazole, and imidazole substrates are well tolerated and generate 40-thionucleoside derivatives containing three contiguous stereogenic centers with excellent results (30 examples, up to 97% yield, 420: 1 dr and up to 99% ee). Moreover, the novel strategy provides an efficient and convenient synthetic route to construct chiral 40-thionucleosides. [ABSTRACT FROM AUTHOR]

A sequential rhodium(III)-catalyzed spiroannulation and lactonization strategy has been developed for the synthesis of a highly rigid spirobenzosultam lactones in good yields with high regioselectivity by means of aromatic ortho-C–H bond activation/functionalization of 3-aryl N-sulfonyl ketimines with 4-hydroxy-2-alkynoates. The reaction proceeds through a cascade of C–H activation followed by spiroannulation and lactonization. In this approach, two C–C and C–O bonds are formed in a single step. This is the first report on the spiroannulation of cyclic N-sulfonyl ketimines with hydroxyalkynoates. [ABSTRACT FROM AUTHOR]

The document is a contents list for the journal "Chemical Communications" published in 2024. It includes various articles on topics such as enantioselective merged gold/organocatalysis, the influence of ion and hydration atmospheres on RNA structure and dynamics, NMR analysis of labeled naphthyridine carbamate dimer, and the synthesis of sydnonimines from sydnones. The journal aims to connect the world with the chemical sciences and is published by The Royal Society of Chemistry. [Extracted from the article]

A palladium-catalyzed enantioselective umpolung allylation reaction of amido-tethered allyl carbonates with N-2,2,2-trifluoroethylisatin ketimines has been realized herein. The reaction worked well under mild reaction conditions to give various chiral oxindole derivatives in moderate to excellent yields with high enantioselectivities. Notably, this work represents the first Pd-catalyzed asymmetric umpolung allylation reaction of N-2,2,2-trifluoroethylisatin ketimines. [ABSTRACT FROM AUTHOR]

We investigate Ti(NEt2)4 supported on silica dehydroxylated at 700 °C as an easily accessible pre-catalyst for oxo/imido heterometathesis reactions. Being activated with TolNH2, the supported Ti amide (≡SiO)Ti(NEt2)3 (1) demonstrates catalytic activity in the imidation of ketones with N-sulfinylamines comparable with the most active previously described well-defined imido catalyst (≡SiO)Ti(＝NtBu)(Me2Pyr)(py)2 (2) (Me2Pyr = 2,5-dimethylpyrrolyl), which implies the in situ formation of surface imido species in this system. The materials obtained via treatment of 1 with anilines (TolNH2 (1a) and p-MeOC6H415NH2 (1b)) were studied with IR, EA and 1H, 13C, 15N and 2D solid-state NMR, although the proposed imido intermediate has not been detected, pointing towards tris-amides (≡SiO)Ti(NHC6H4X)3 (X = Me, OMe) being the major surface species in the isolated materials 1a and 1b. The system 1/TolNH2 was tested in a range of imidation reactions and demonstrated excellent performance for express high-yielding preparation of ketimines, formamidines, lactone imidates and sulfurdiimines, making it a convenient alternative to the well-defined supported Ti imido catalysts. [ABSTRACT FROM AUTHOR]

This article introduces a reductive coupling driven by visible-light, facilitating the synthesis of pyridine-substituted alcohols and amines through the reaction of aldehydes, ketones and imines with cyanopyridines. Hantzsch esters serve as reductants in this process, eliminating the need for transition-metals or photosensitizers. The method demonstrates extensive compatibility and finds utility in the late-stage functionalization of both natural and pharmaceutical products, offering a sustainable pathway for the diversification of chemical compounds. [ABSTRACT FROM AUTHOR]

The highly efficient reductive amination of aldehydes with ammonia (NH3) and hydrogen (H2) to form secondary imines is described, as well as the dehydrogenative homocoupling of benzyl amines. Using an air-stable, well-defined PN3-manganese(II) pincer complex as a catalyst precursor, various aldehydes are easily converted directly into secondary imines using NH3 as a nitrogen source under H2 in a one-pot reaction. Importantly, the same catalyst facilitates the dehydrogenative homocoupling of various benzylamines, exclusively forming imine products. These reactions are conducted under very mild conditions, without the addition of any additives, yielding excellent selectivities and high yields of secondary imines in a green manner by minimizing wastes. [ABSTRACT FROM AUTHOR]

The first catalytic enantioselective [5+1] cycloaddition reactions of C,N-cyclic azomethine imines with isocyanides are reported herein. The method displays a broad substrate scope and atom-economy. A series of chiral tetrahydroisoquinoline containing indole skeletons were obtained in up to 90% yield with 95% ee under mild reaction conditions. A possible catalytic model was also proposed. [ABSTRACT FROM AUTHOR]

Five new alkylaluminum complexes with different pyridinyl-substituted imines or cyclohexyl-substituted imines were synthesized and characterized successfully. The aluminum complex [FlCHNCH(CH3)Py]AlMe2(Py = 2-pyridyl) (1) was obtained by reacting 9-[2-pyridyl-CH(CH3)-N＝CH]Fl (Fl = fluorenyl) (L1) and equimolar AlMe3. The reactions of 9-(2-pyridyl-N＝CH)Fl (L2) and 9-[2-N(CH3)2-cyclohexyl-N＝CH]Fl (L3) with equimolar AlMe3 or AlEt3 afforded other alkylaluminum complexes [FlCHNPy]AlMe2(Py = 2-pyridyl) (2), [FlCHNPy]AlEt2 (Py = 2-pyridyl) (3), [FlCHNCyN(CH3)2]AlMe2 (Cy = 2-cyclohexyl) (4) and [FlCHNCyN(CH3)2]AlEt2 (Cy = 2-cyclohexyl) (5). All these complexes (1–5) were characterized using NMR spectroscopy, elemental analysis, and X-ray crystal structure analysis. The catalytic properties of these new alkylaluminum complexes for the hydrophosphonylation of aldimines were examined. Complex 5 showed the best catalytic performance under mild reaction conditions with a low catalyst loading (1 mol%), and 20 different substituents of aldimines were isolated with more than 90% yields. [ABSTRACT FROM AUTHOR]

Bismuth(III) triflate-catalyzed [4+2]-annulation of cyclic N-sulfonyl ketimines (derived from saccharin) and alkynyl alcohols (4-pentyn-1-ols and 5-hexyn-1-ols) has been reported. This cascade annulation provides a diverse array of polycyclic spiro-and-fused N,O-ketals with excellent substrate scope, good isolated yields, and diastereoselectivities under mild reaction conditions. [ABSTRACT FROM AUTHOR]

Ternary NiTiFe-LDH with an ultrathin nanosheet morphology was successfully fabricated via a facile co-precipitation method, followed by refluxing, and was used as a catalyst for oxidative coupling of amines to produce imines under visible light. The obvious superior activity observed in NiTiFe-LDH ultrathin nanosheets compared with binary NiTi-LDH and bulk NiTiFe-LDH can be ascribed to an enhanced light absorption capability caused by the introduction of Fe3+ ions as well as the ultrathin nanosheets which can minimize the recombination of the photogenerated charge carriers and provide more catalytically active sites for the reaction. As a result, more catalytically active O2˙− radicals are generated over NiTiFe-LDH ultrathin nanosheets, which leads to their superior activity. This study not only shows the possibility of using LDHs in photocatalytic organic transformations but also demonstrates an effective strategy to promote the activity of LDH-based photocatalysts via simultaneous composition and morphology modulation of LDHs. [ABSTRACT FROM AUTHOR]

Rhodium-catalyzed three-component C–H bond activation of aromatics with amides and aldehydes to synthesize amines was established. The addition of copper was found to be essential to ensure the high reactivity. The mechanistic studies indicated that key intermediates formed by the transmetallization between rhodium and copper could further promote the addition between 2-(pyridin-2-yl)-phenyl-metal species and imines. A series of densely substituted amines could be conveniently prepared by this one-step, three-component procedure from commercially available substrates via C–H bond activation with water as the only by-product. [ABSTRACT FROM AUTHOR]

Covalent organic frameworks (COFs) are a prominent class of organic materials constructed from versatile building blocks via reversible reactions. The quality of imine-linked COFs can be improved by using amine monomers protected with benzophenone forming benzophenone imines. Here, we present a study on substituted benzophenones in COF synthesis via formal transimination. 12 para-substituted N-aryl benzophenone imines, with a range of electron-rich to electron-poor substituents, were prepared and their hydrolysis kinetics were studied spectroscopically. All substituted benzophenone imines can be employed in COF synthesis and lead to COFs with high crystallinity and high porosity. The substituents act innocent to COF formation as the substituted benzophenones are cleaved off. Imines can be tailored to their synthetic demands and utilized in COF formation. This concept can make access to previously unattainable, synthetically complex COF monomers feasible. [ABSTRACT FROM AUTHOR]

A synthetic method to prepare 1-alkyl-substituted-pyrazolidin-3-ones efficiently that relies on the 4CzPN-mediated alkylation of azomethine imines by 4-alkyl-substituted-1,4-dihydropyridines (DHPs) under blue light emitting diode (LED) light (λmax = 456 nm) is reported. An approach that exploits the ability of blue LED light to initiate the acylation of the imine substrate by 4-acyl-substituted-DHPs to give 1-acyl-substituted-pyrazolidin-3-ones is also presented. Achieved under mild reaction conditions at room temperature, the synthetic protocol was shown to tolerate a broad range of functional groups to afford the corresponding 1-substituted-pyrazolidin-3-ones in yields up to 99%. [ABSTRACT FROM AUTHOR]

Reactions between imines and tungsten alkylidyne complexes are studied. The trianionic pincer ligand supported alkylidyne [tBuOCO]WCC(CH3)3(THF)2 (1) reacts with N-(R)-1-phenylmethanimine (PMI-R, R = Me, Ph, Bn, and TMS) yielding [tBuOC(H)O]W(η2-tBuC≡CPh)N(R) (4-R), products from metathesis reaction. In contrast, the non-pincer alkylidyne (tBuO)3W≡CC(CH3)3 does not react with PMI-R imines. [ABSTRACT FROM AUTHOR]

Using a formate salt as a promising hydrogen carrier and one-carbon (C1) source, we have developed a novel and practical method for the preparation of α-amino acid derivatives under mild conditions. In this approach, the photoexcited naphthalene thiolate acts simultaneously as a photoexcited single-electron reductant and a hydrogen atom transfer (HAT) catalyst, enabling efficient metal-free radical–radical cross-coupling of formate with ketimines and aldimines. [ABSTRACT FROM AUTHOR]

Imines play a fundamental role in organic synthesis and some of them have been detected in space. However, the simplest imines are spectroscopically not well-characterized. Herein we present the infrared and UV/Vis spectroscopic characterization of 2-iminoacetaldehyde using cryogenic matrix isolation techniques. After UV irradiation of 2-azidoacetaldehyde in solid argon at 3 K we identified two conformers of 2-iminoacetaldehyde, which can be photochemically interconverted. Deuterium labelling experiments and high level ab initio coupled cluster calculations at the CCSD(T)/CBS level of theory provide further evidence for the formation of 2-iminoacetaldehyde. [ABSTRACT FROM AUTHOR]

A highly enantioselective Michael addition between benzophenone-imine of glycine esters and β-substituted α,β-unsaturated pyrazolamides has been realized by using 10 mol% of a chiral cyclopropenimine (Lambert catalyst, CSB-1) as an organosuperbase catalyst under very mild conditions to afford Michael adducts in up to 95% yield and 99% ee. The pyroglutamic acid esters with two adjacent stereocenters are obtained through subsequent lactamization in quantitative yields and excellent enantioselectivities. [ABSTRACT FROM AUTHOR]

The reductive coupling of dienol ethers with N-tosylimines catalyzed by Ni(0) in the presence of a VAPOL-derived phosphoramidite ligand follows an unprecedented regiochemical course; it furnishes syn-configured 1,2-aminoalcohol derivatives in good chemical yields with up to 94% ee. [ABSTRACT FROM AUTHOR]

The synthesis and properties of photoswitchable electron-rich phosphines containing N-heterocyclic imines equipped with a photochromic dithienylethene unit are reported. Heteronuclear NMR spectroscopy and UV/vis studies reveal that the imine substituents undergo reversible electrocyclic ring-closing and ring-opening reactions upon exposure to UV and visible light, respectively. The photoisomerization alters the electron-donating ability of the phosphines by up to ΔTEP = 8 cm−1. [ABSTRACT FROM AUTHOR]

Despite p-block clusters being known for over a century, their application as catalysts to mediate organic transformations is underexplored. Here, the boron functionalized [P7] cluster [(BBN)P7]2- ([1]²-; BBN = 9-borabicyclo[3.3.1]nonane) is applied in the dearomatized reduction of pyridines, as well as the hydroboration of imines and nitriles. These transformations afford amine products, which are important precursors to pharmaceuticals, agrochemicals, and polymers. Catalyst [1]2- has high stability in these reductions: recycling nine times in quinoline hydroboration led to virtually no loss in catalyst performance. The catalyst can also be recycled between two different organic transformations, again with no loss in catalyst competency. The mechanism for pyridine reduction was probed experimentally using variable time normalization analysis, and computationally using density functional theory. This work demonstrates that Zintl clusters can mediate the reduction of nitrogen containing substrates in a transition metal-free manner. [ABSTRACT FROM AUTHOR]

A combination of Ga(I) centers as important building blocks and scaffolds containing N-heterocyclic imines gives new insights into low-valent Ga chemistry. In this study, a mixture of LDipNLi (LDip = 1,3-bis(2,6-diisopropylphenyl)-imidazolin-2-ylidene), tBuOK, and Cp*Ga (Cp* = pentamethylcyclopentadienyl) in toluene afforded [LDipN-Ga]2 (1) via salt metathesis. X-ray structure analysis of 1 revealed a four-membered Ga2N2 ring, and DFT studies indicated the presence of a lone pair at each Ga center. In addition, compound 1 demonstrated diverse reactivities towards methyl trifluoromethanesulfonate, diphenyl disulfide, 9,10-phenanthrenequinone, and ECl2 (E = Ge or Sn). [ABSTRACT FROM AUTHOR]

α-Amino ketones are important motifs in synthetic and medicinal chemistry. Efficient methods to directly access these motifs from feasible precursors are, however, limited. Herein, a visible-light mediated reductive cross-electrophile coupling of readily available imines and anhydrides was developed. Under mild reaction conditions, the umpolung reactivity of diverse imines engaged with anhydrides gives a variety of α-amino ketones with good yields and a broad functional group compatibility. Primary mechanistic studies revealed that this transformation might proceed through a radical–radical cross coupling pathway dominantly. [ABSTRACT FROM AUTHOR]

The first examples of regioselective aryl ortho-C–H functionalization with diphenyldiazomethane for the construction of Caryl–Nhydrazinato bonds were accomplished via the activation of C–H bonds and the subsequent reaction of diphenyldiazomethane with the RE–Caryl bond. The reactions of rare-earth metal monoalkyl complexes LRE(CH2SiMe3)(THF)2 (L = 2,5-[(2-pyrrolyl)CPh2]2(N-Me-pyrrole)) supported by a neutral N-methylpyrrole anchored dipyrrolyl ligand with 2 equiv. of Ph2CN2 gave irreversibly unprecedented hydrazonato-functionalized imino rare-earth metal complexes LRE(Ph2C＝NNC6H4-(o-C＝NHPh) (RE = Y (2a), Lu (2a′)) in good yields involving a rather complex process including the interaction of a diazo unit with a RE–Calkyl bond, a β-H elimination, a N–N cleavage, 1,4-hydrogen transfer and the subsequent C–N coupling with another diphenyldiazomethane. More important is that regioselective aryl C–H bond functionalization with diphenyldiazomethane to construct the Caryl–Nhydrazinato bonds can be easily achieved by three-component reactions of rare-earth metal monoalkyl complexes, a wide range of substituted imines (including aldimines, ketimines or analogous 2-phenylpyridine) and diphenyldiazomethane, affording various hydrazonato-functionalized phenyl, thienyl imino or pyridyl rare-earth metal complexes 2b–2j at room temperature. A further study indicated that the substituents on the phenyl ring have a great effect on the reaction pathway and governed the Caryl–Nhydrazinato bond construction. Moreover, the experimental studies show that the formation of the Caryl–Nhydrazinato bonds is thermodynamically facile, which could be realized at room temperature easily. [ABSTRACT FROM AUTHOR]

A highly efficient protocol for stereoselective synthesis of novel polycyclic benzo[b]thiophene derivatives was developed. Using quinine-derived bifunctional thiourea (5 mol%) as a catalyst, asymmetric [3+3] annulation of N-(benzo[b]thiophen-2-yl)-sulfonamide with 2-alkynyl cycloenone could provide dihydrobenzo[4,5]thieno[2,3-b]pyridine derivatives in moderate to good yields (up to 93%) with mostly excellent enantioselectivities (up to 97% ee) under mild conditions. In addition, large-scale experiments and derivatizations were explored. In particular, the target product in large-scale experiments could be easily purified by filtration and the filtrated product showed >99% ee. [ABSTRACT FROM AUTHOR]

The reaction of [Ru(PPh3)3Cl2] with a group of four 1,4-diazabutadiene ligands (p-RC6H4N＝C(H)–C(H)＝NC6H4R-p; R = OCH3, CH3, H and Cl; abbreviated as L-R) in an equimolar ratio afforded chloro-bridged di-ruthenium complexes (1–4) of the general type [Ru2(PPh3)2(L-R)2Cl3]Cl. The crystal structures of complexes 1 (R = OCH3), 2 (R = CH3) and 4 (R = Cl) were determined and the molecular structure of complex 3 (R = H) was optimized using the DFT method. Each complex showed four intense absorptions in the visible and ultraviolet regions, the origin of which was probed employing TDDFT calculations. The complexes were found to serve as efficient catalyst precursors for the oxidative and deaminative C–N coupling of a series of primary amines, producing corresponding imines in good yields. Homo-coupling of benzylamines and cross-coupling of two differently substituted benzylamines or benzylamine with anilines and other aryl/alkyl amines could be realized using this catalytic protocol with aerial oxygen as the oxidant. [ABSTRACT FROM AUTHOR]

With formaldehyde as an atom-economical carbonyl synthon, the EtOH-catalyzed electrochemical multicomponent synthesis of various imidazolidine-fused sulfamidates was developed. A wide range of products were obtained in good to excellent yields under organic oxidant-free, energy-saving and mild conditions. The mechanistic study revealed that the in situ generated ethoxide played a crucial role in producing aminomethylene radicals at a lower voltage. [ABSTRACT FROM AUTHOR]

A crucial step in the formation of mono-aminoboranes (R2N–BH2) from the corresponding imine–BH3 adducts, under mild reaction conditions, is the 1,3-hydride shift. We offer experimental and theoretical insights into this molecular rearrangement according to two mechanistic pathways: intra-molecular (unimolecular) and inter-molecular (bimolecular). Even though a few experimental observations were inconclusive, an isotope-based experiment suggested that the 1,3-hydride shift occurs bimolecularly. In addition, the shape of the potential energy landscape, generated via the computational means, strongly suggests that these reactions are bimolecular. Relative energy gradient analysis enabled to identify the driving forces according to both scenarios and to explain the unusual shape of the minimum energy path in a unimolecular process. Our results imply that elevated temperature (60 °C) supplies the reactants with sufficient energy to cross the barrier, whereby each collision with properly oriented reactants results in mono-aminoborane formation. [ABSTRACT FROM AUTHOR]

Using binaphthyl-proline-based chiral ligands, Zn(II)-catalysed addition of alcohols and tert-butyl hydroperoxide to isatin-derived N-Boc ketimines provided the isatin-derived C3 N,O-aminals in up to 99% yield and up to 99% ee. The reactions could be carried out under mild conditions and a gram-scale reaction could be realized without the loss of the yield and enantioselectivity. [ABSTRACT FROM AUTHOR]

A manganese catalyst of a facially coordinating P,N,N ligand catalyses the hydrogenation of imines derived from indanone derivatives with high enantioselectivity. There is no requirement for an activating group and imines can be generated in situ. The selectivity can be rationalised by DFT calculations. [ABSTRACT FROM AUTHOR]

The significance of chiral α-tertiary amines in medicinal chemistry and drug development has been unquestionably established in the last few decades. α-Tertiary amines are attractive structural motifs for natural products, bioactive molecules and pharmaceuticals and are preclinical candidates. Their syntheses have been the focus of intensive research, and the development of new methods has continued to attract more and more attention. In this review, we present the progress in the last decade in the development of synthetic methods for the assembly of chiral ATAs via transition-metal catalysis. To date, the effective approaches in this area could be categorized into three strategies: enantioselective direct and indirect Mannich addition to ketimines; umpolung asymmetric alkylation of imine derivatives; and asymmetric C–N cross-coupling of tertiary alkyl electrophiles. Several related developing strategies for the synthesis of ATAs, such as hydroamination of alkenes, HAT amination approaches and the C–C coupling of α-aminoalkyl fragments, are also described in this article. These strategies have emerged as attractive C–C and C–N bond-forming protocols for enantioselective construction of chiral α-tertiary amines, and to some extent are complementary to each other, showing the prospect of application in medicinal chemistry and chemical biology. [ABSTRACT FROM AUTHOR]

The synthesis of a new porous organic cage decorated with isopropyl moieties (CC21) was achieved from the reaction of triformylbenzene and an isopropyl functionalised diamine. Unlike structurally analogous porous organic cages, its synthesis proved challenging due to competitive aminal formation, rationalised using control experiments and computational modelling. The use of an additional amine was found to increase conversion to the desired cage. [ABSTRACT FROM AUTHOR]

The direct C2-addition of 5H-oxazol-4-ones to γ-keto-α,β-unsaturated esters catalyzed by a chiral squaramide has been achieved. Diverse highly functionalized γ-keto esters bearing a C2-oxazolone at the α-position were afforded in high yields with excellent stereoselectivities (d.r. > 20 : 1 and up to 98% ee). [ABSTRACT FROM AUTHOR]

This report discusses the reactivities of hydroxylamines with a family of nickellacyclic complexes prepared by C–H nickellation of aryl phosphinites. Treating the dimeric complexes κC,κP-{2-OPR2,4-R′-C6H4}2Ni2(μ-Br)2 (R = i-Pr; R′ = H, Cl, OMe, NMe2) or their monomeric acetonitrile adducts κC,κP-{2-OPR2,4-R′-C6H4}Ni(Br)(NCMe) with hydroxylamines showed three types of reactivities depending on the Ni complex, the reaction solvent, and the substrate used: (1) the benzyl-protected substrate PhCH2ONH2 gave simple N-bound adducts with all Ni complexes; (2) the parent Ni dimer (R′ = H) reacted with Et2NOH and (PhCH2)2NOH in CH2Cl2 to give, respectively, the zwitterionic amine oxide κC,κP-{2-OPR2-C6H5}Ni(κO-ONHEt2)Br and the bidentate aminoxide (i-R2POPh)Ni{κO,κN-ON(CH2Ph)2}Br; (3) the analogous reaction of substituted Ni complexes (R′ = Cl, OMe, NMe2) with hydroxylamines in acetonitrile gave adducts of imines derived from dehydration of Et2NOH and (PhCH2)2NOH. The latter reactivity proceeds optimally in acetonitrile, but it also occurs to a lesser extent in C6D6 if the reaction is allowed to go for more than 24 h. Different mechanistic scenarios have been considered to rationalize the observed hydroxylamine → imine transformation. [ABSTRACT FROM AUTHOR]

An engineered (S)-selective imine reductase from Streptomyces sp. GF3546 (SIR46) showed twice the activity of the wild type and high thermostability at 50 °C. Using a biocatalyst based on SIR46, we investigated the activity toward high-concentration 2-methyl-1-pyrroline up to 500 mM, conversion rates of other imines, and reductive amination activity. [ABSTRACT FROM AUTHOR]

In this report, we developed a photocatalyst-free visible-light-promoted deoxygenative alkylation of imines with alcohols assisted by carbon disulfide and tricyclohexylphosphine. The key to success of this method is the activation of alcohols upon the formation and direct photoexcitation of xanthate anions. This one-pot protocol enables the selective C–O bond homolysis of diverse primary, secondary and tertiary alcohols to react with a variety of N-sulfonyl and N-aryl imines, providing a general and efficient platform for α-branched amine synthesis from alcohols. [ABSTRACT FROM AUTHOR]

An efficient organocatalyzed enantioselective hydrophosphinylation of indole-derived vinylogous imines generated in situ from sulfonyl indoles has been developed. Using quinine-derived bifunctional thiourea as the catalyst, a wide range of structurally diverse chiral 3-(1-diphenylphosphoryl-arylmethyl)indoles were obtained with good to excellent results (up to 99% yield and 99% ee). This method represents the first example of the catalytic asymmetric Michael addition of phosphine oxides to vinylogous imine intermediates. [ABSTRACT FROM AUTHOR]